Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
I just took another look at the schematic you provided, you're right. You don't need to do cathode side blanking. For some reason, I thought that you had both nixies in the pair connected to the same 74141 and would need to blank cathode side in order to address a single nixie. Since you have each nixie in the pair connected to a separate 74141, you should be fine. -Adam On 3/26/2012 12:13 PM, Imbanon wrote: Indeed, I see you got it right :) Anyhow, I got it all fixed. I just lowered the power supply to 180V. Of course, I had to recalculate all the anode resistors (finally have individal anode resistors), but the blanking now works just fine. But still, I don't understand why I should blank one nixie in an anode pair, like Adam suggested. Also, sequence like that will cut the duty cycle by half, meaning I would need to increase the current peak, and lower the tube life. It does seem to work fine as is. Ok, Good luck. Thanks a lot! On Mar 22, 11:27 pm, Cobra007 wrote: It's an interesting combination those 2 npn transistors. The signal on the base is actually inverted compared to "normal" npn/pnp transistors. When T2, T3, T5 are switched off, the tubes are actually on :-). That's also where your leakage problem comes from if you ask me. You choose 220k resistors, which means the lowest possible anode voltage is half the supply voltage (215V / (220k + 220k)) * 220k = 107.5V. You better choose a lower resistor that goes to the collector of T2, T3, T5 (maybe 100k). This will bring the anode voltage down to about 68V. I don't have a price yet for my modules, they won't be expensive of course but I need to wait until I have a finished product. Michel On Mar 23, 5:00 am, Imbanon wrote: Sorry about that. I thought it was an universal shematic file type, 'cause they are all .sch Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729 Cheers On Mar 22, 4:14 pm, Adam Jacobs wrote: Would you mind converting that schematic to some kind of image file? Is that an eaglecad file? blanking on the 74141 will cause leakage if the supply voltage is too high. Are you using real 74141's or the russian kind? From that picture, I'm not sure if that is leakage. -Adam On 3/22/2012 5:19 AM, Imbanon wrote: Hey all I found some time to make a schematic. It only shows the two 74141, nixie tubes and anode drivers. I also tried blanking nixies via 74141. I would have never guessed that you meant on hex code, as I am doing this on an arduino :) Blanking nixies with 74141's give me a lot of leaking (or at least I think thats leaking), so I'm not so sure about using this method. But I do think that it's maybe possible to divide the leaking to the rest of the nixies by adding a resistor for each anode, instead of sharing them. See for yourself in the links. http://www.mediafire.com/download.php?bbx4z4k5vjul56b http://www.mediafire.com/download.php?ym4s96yeusrm9sy So I guess my next move should be to remove the trimpots, and replace them with actual resistors for each anode. But what should I do with the blanking? To be honest, I would leave the setup as is, because it seems to work fine. But if you guys think I can do something better to get a longer tube life, I will make changes to the schematic immediately. Thanks! On Mar 19, 12:04 am, Dylan Distasiowrote: I'm very interested in hearing more about this module...Are you saying you are having this custom manufactured? If so, how have you found a way to do this economically? On Sun, Mar 18, 2012 at 6:31 PM, Cobra007wrote: For my clock I am designing a module as I am not really a fan to use these types of old TTL logic. It's a 24 pin module that fits into a DIP24 IC socket. It basically mimics the 74141 but has high voltage output mosfets (240V) and the 4 inputs can be latched, so you don't need extra latches as required by the standard 74141. It also offers a blanking input, either by writing 0x0a or using a dedicated pin (which is convenient for PWM dimming). It can be interfaced with MCU or arduino. Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Indeed, I see you got it right :) Anyhow, I got it all fixed. I just lowered the power supply to 180V. Of course, I had to recalculate all the anode resistors (finally have individal anode resistors), but the blanking now works just fine. But still, I don't understand why I should blank one nixie in an anode pair, like Adam suggested. Also, sequence like that will cut the duty cycle by half, meaning I would need to increase the current peak, and lower the tube life. It does seem to work fine as is. > Ok, Good luck. Thanks a lot! On Mar 22, 11:27 pm, Cobra007 wrote: > It's an interesting combination those 2 npn transistors. The signal on > the base is actually inverted compared to "normal" npn/pnp > transistors. When T2, T3, T5 are switched off, the tubes are actually > on :-). That's also where your leakage problem comes from if you ask > me. You choose 220k resistors, which means the lowest possible anode > voltage is half the supply voltage (215V / (220k + 220k)) * 220k = > 107.5V. You better choose a lower resistor that goes to the collector > of T2, T3, T5 (maybe 100k). This will bring the anode voltage down to > about 68V. > > I don't have a price yet for my modules, they won't be expensive of > course but I need to wait until I have a finished product. > > Michel > > On Mar 23, 5:00 am, Imbanon wrote: > > > > > > > > > Sorry about that. I thought it was an universal shematic file type, > > 'cause they are all .sch > > > Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729 > > Cheers > > > On Mar 22, 4:14 pm, Adam Jacobs wrote: > > > > Would you mind converting that schematic to some kind of image file? Is > > > that an eaglecad file? > > > > blanking on the 74141 will cause leakage if the supply voltage is too > > > high. Are you using real 74141's or the russian kind? > > > From that picture, I'm not sure if that is leakage. > > > > -Adam > > > > On 3/22/2012 5:19 AM, Imbanon wrote: > > > > > Hey all > > > > > I found some time to make a schematic. It only shows the two 74141, > > > > nixie tubes and anode drivers. > > > > I also tried blanking nixies via 74141. I would have never guessed > > > > that you meant on hex code, as I am doing this on an arduino :) > > > > Blanking nixies with 74141's give me a lot of leaking (or at least I > > > > think thats leaking), so I'm not so sure about using this method. But > > > > I do think that it's maybe possible to divide the leaking to the rest > > > > of the nixies by adding a resistor for each anode, instead of sharing > > > > them. See for yourself in the links. > > > > >http://www.mediafire.com/download.php?bbx4z4k5vjul56b > > > >http://www.mediafire.com/download.php?ym4s96yeusrm9sy > > > > > So I guess my next move should be to remove the trimpots, and replace > > > > them with actual resistors for each anode. > > > > But what should I do with the blanking? To be honest, I would leave > > > > the setup as is, because it seems to work fine. But if you guys think > > > > I can do something better to get a longer tube life, I will make > > > > changes to the schematic immediately. > > > > > Thanks! > > > > > On Mar 19, 12:04 am, Dylan Distasio wrote: > > > >> I'm very interested in hearing more about this module...Are you saying > > > >> you > > > >> are having this custom manufactured? If so, how have you found a way > > > >> to do > > > >> this economically? > > > > >> On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > > > > >>> For my clock I am designing a module as I am not really a fan to use > > > >>> these types of old TTL logic. It's a 24 pin module that fits into a > > > >>> DIP24 IC socket. It basically mimics the 74141 but has high voltage > > > >>> output mosfets (240V) and the 4 inputs can be latched, so you don't > > > >>> need extra latches as required by the standard 74141. It also offers a > > > >>> blanking input, either by writing 0x0a or using a dedicated pin (which > > > >>> is convenient for PWM dimming). It can be interfaced with MCU or > > > >>> arduino. > > > >>> Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
On Friday, 16 March 2012 19:22:05 UTC, Imbanon wrote: > > Oh and I accidentaly reported your post as spam. Sorry about that! > Dunno how that effects anything though.. > It doesn't - the mods clean up behind you ;-) -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/tTQcMcycOJkJ. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
On Thursday, March 22, 2012 11:12:21 AM UTC-7, Adam Jacobs wrote: > > The resistor between the base of the PNP and the collector of the PNP > should be more like 10k. > > > More like between base and emitter, to speed up turn-off time. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/djdnwTLUahYJ. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
It's an interesting combination those 2 npn transistors. The signal on the base is actually inverted compared to "normal" npn/pnp transistors. When T2, T3, T5 are switched off, the tubes are actually on :-). That's also where your leakage problem comes from if you ask me. You choose 220k resistors, which means the lowest possible anode voltage is half the supply voltage (215V / (220k + 220k)) * 220k = 107.5V. You better choose a lower resistor that goes to the collector of T2, T3, T5 (maybe 100k). This will bring the anode voltage down to about 68V. I don't have a price yet for my modules, they won't be expensive of course but I need to wait until I have a finished product. Michel On Mar 23, 5:00 am, Imbanon wrote: > Sorry about that. I thought it was an universal shematic file type, > 'cause they are all .sch > > Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729 > Cheers > > On Mar 22, 4:14 pm, Adam Jacobs wrote: > > > > > > > > > Would you mind converting that schematic to some kind of image file? Is > > that an eaglecad file? > > > blanking on the 74141 will cause leakage if the supply voltage is too > > high. Are you using real 74141's or the russian kind? > > From that picture, I'm not sure if that is leakage. > > > -Adam > > > On 3/22/2012 5:19 AM, Imbanon wrote: > > > > Hey all > > > > I found some time to make a schematic. It only shows the two 74141, > > > nixie tubes and anode drivers. > > > I also tried blanking nixies via 74141. I would have never guessed > > > that you meant on hex code, as I am doing this on an arduino :) > > > Blanking nixies with 74141's give me a lot of leaking (or at least I > > > think thats leaking), so I'm not so sure about using this method. But > > > I do think that it's maybe possible to divide the leaking to the rest > > > of the nixies by adding a resistor for each anode, instead of sharing > > > them. See for yourself in the links. > > > >http://www.mediafire.com/download.php?bbx4z4k5vjul56b > > >http://www.mediafire.com/download.php?ym4s96yeusrm9sy > > > > So I guess my next move should be to remove the trimpots, and replace > > > them with actual resistors for each anode. > > > But what should I do with the blanking? To be honest, I would leave > > > the setup as is, because it seems to work fine. But if you guys think > > > I can do something better to get a longer tube life, I will make > > > changes to the schematic immediately. > > > > Thanks! > > > > On Mar 19, 12:04 am, Dylan Distasio wrote: > > >> I'm very interested in hearing more about this module...Are you saying > > >> you > > >> are having this custom manufactured? If so, how have you found a way to > > >> do > > >> this economically? > > > >> On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > > > >>> For my clock I am designing a module as I am not really a fan to use > > >>> these types of old TTL logic. It's a 24 pin module that fits into a > > >>> DIP24 IC socket. It basically mimics the 74141 but has high voltage > > >>> output mosfets (240V) and the 4 inputs can be latched, so you don't > > >>> need extra latches as required by the standard 74141. It also offers a > > >>> blanking input, either by writing 0x0a or using a dedicated pin (which > > >>> is convenient for PWM dimming). It can be interfaced with MCU or > > >>> arduino. > > >>> Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
Ok, Good luck. On 3/22/2012 12:05 PM, Imbanon wrote: Why would you say something like that? What's wrong with using trimpots instead of resistors when you're not home with your stuff? Or using NPN based anode drivers.. Why would I NEED to make a so popular NPN-PNP anode driver, when I first thought of something like this, with parts I already had. And it all seems to work. And sorry, no I haven't heard that one. Nothing like that in my language. On Mar 22, 7:45 pm, Adam Jacobs wrote: I'm starting to get the impression that this is a parts-box project. Have you ever heard the expression that when the only tool you have is a hammer, everything starts looking like a nail? On 3/22/2012 11:42 AM, Imbanon wrote: Please take note that I am not using PNP's at all, only NPN's :) On Mar 22, 7:12 pm, Adam Jacobswrote: _MUCH_ better. Okay, firstly this design can work - there's nothing fundamentally wrong with it. Like I said, you'll need to be able to make cathode-side blanking (74141) work if you're going to stick with only 3 anode drivers. 1) Your anode drivers aren't quite right. The resistor on the base of the NPN should be more like 10k (R1). You're missing the pulldown on the base as well. Add a 10k between the base of the NPN and GND. The resistor between the collector of the NPN and the base of the PNP should be more like 1M. The resistor between the base of the PNP and the collector of the PNP should be more like 10k. 2) The reason that you are getting current leakage with the 74141 is because your HV supply is too high. Instead of 215v, use 180v. -Adam On 3/22/2012 11:00 AM, Imbanon wrote: Sorry about that. I thought it was an universal shematic file type, 'cause they are all .sch Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729 Cheers On Mar 22, 4:14 pm, Adam Jacobs wrote: Would you mind converting that schematic to some kind of image file? Is that an eaglecad file? blanking on the 74141 will cause leakage if the supply voltage is too high. Are you using real 74141's or the russian kind? From that picture, I'm not sure if that is leakage. -Adam On 3/22/2012 5:19 AM, Imbanon wrote: Hey all I found some time to make a schematic. It only shows the two 74141, nixie tubes and anode drivers. I also tried blanking nixies via 74141. I would have never guessed that you meant on hex code, as I am doing this on an arduino :) Blanking nixies with 74141's give me a lot of leaking (or at least I think thats leaking), so I'm not so sure about using this method. But I do think that it's maybe possible to divide the leaking to the rest of the nixies by adding a resistor for each anode, instead of sharing them. See for yourself in the links. http://www.mediafire.com/download.php?bbx4z4k5vjul56b http://www.mediafire.com/download.php?ym4s96yeusrm9sy So I guess my next move should be to remove the trimpots, and replace them with actual resistors for each anode. But what should I do with the blanking? To be honest, I would leave the setup as is, because it seems to work fine. But if you guys think I can do something better to get a longer tube life, I will make changes to the schematic immediately. Thanks! On Mar 19, 12:04 am, Dylan Distasiowrote: I'm very interested in hearing more about this module...Are you saying you are having this custom manufactured? If so, how have you found a way to do this economically? On Sun, Mar 18, 2012 at 6:31 PM, Cobra007wrote: For my clock I am designing a module as I am not really a fan to use these types of old TTL logic. It's a 24 pin module that fits into a DIP24 IC socket. It basically mimics the 74141 but has high voltage output mosfets (240V) and the 4 inputs can be latched, so you don't need extra latches as required by the standard 74141. It also offers a blanking input, either by writing 0x0a or using a dedicated pin (which is convenient for PWM dimming). It can be interfaced with MCU or arduino. Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Why would you say something like that? What's wrong with using trimpots instead of resistors when you're not home with your stuff? Or using NPN based anode drivers.. Why would I NEED to make a so popular NPN-PNP anode driver, when I first thought of something like this, with parts I already had. And it all seems to work. And sorry, no I haven't heard that one. Nothing like that in my language. On Mar 22, 7:45 pm, Adam Jacobs wrote: > I'm starting to get the impression that this is a parts-box project. > Have you ever heard the expression that when the only tool you have is a > hammer, everything starts looking like a nail? > > On 3/22/2012 11:42 AM, Imbanon wrote: > > > > > > > > > Please take note that I am not using PNP's at all, only NPN's :) > > > On Mar 22, 7:12 pm, Adam Jacobs wrote: > >> _MUCH_ better. > > >> Okay, firstly this design can work - there's nothing fundamentally wrong > >> with it. Like I said, you'll need to be able to make cathode-side > >> blanking (74141) work if you're going to stick with only 3 anode drivers. > > >> 1) Your anode drivers aren't quite right. The resistor on the base of > >> the NPN should be more like 10k (R1). You're missing the pulldown on the > >> base as well. Add a 10k between the base of the NPN and GND. The > >> resistor between the collector of the NPN and the base of the PNP should > >> be more like 1M. The resistor between the base of the PNP and the > >> collector of the PNP should be more like 10k. > > >> 2) The reason that you are getting current leakage with the 74141 is > >> because your HV supply is too high. Instead of 215v, use 180v. > > >> -Adam > > >> On 3/22/2012 11:00 AM, Imbanon wrote: > > >>> Sorry about that. I thought it was an universal shematic file type, > >>> 'cause they are all .sch > >>> Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729 > >>> Cheers > >>> On Mar 22, 4:14 pm, Adam Jacobs wrote: > Would you mind converting that schematic to some kind of image file? Is > that an eaglecad file? > blanking on the 74141 will cause leakage if the supply voltage is too > high. Are you using real 74141's or the russian kind? > From that picture, I'm not sure if that is leakage. > -Adam > On 3/22/2012 5:19 AM, Imbanon wrote: > > Hey all > > I found some time to make a schematic. It only shows the two 74141, > > nixie tubes and anode drivers. > > I also tried blanking nixies via 74141. I would have never guessed > > that you meant on hex code, as I am doing this on an arduino :) > > Blanking nixies with 74141's give me a lot of leaking (or at least I > > think thats leaking), so I'm not so sure about using this method. But > > I do think that it's maybe possible to divide the leaking to the rest > > of the nixies by adding a resistor for each anode, instead of sharing > > them. See for yourself in the links. > >http://www.mediafire.com/download.php?bbx4z4k5vjul56b > >http://www.mediafire.com/download.php?ym4s96yeusrm9sy > > So I guess my next move should be to remove the trimpots, and replace > > them with actual resistors for each anode. > > But what should I do with the blanking? To be honest, I would leave > > the setup as is, because it seems to work fine. But if you guys think > > I can do something better to get a longer tube life, I will make > > changes to the schematic immediately. > > Thanks! > > On Mar 19, 12:04 am, Dylan Distasio wrote: > >> I'm very interested in hearing more about this module...Are you saying > >> you > >> are having this custom manufactured? If so, how have you found a way > >> to do > >> this economically? > >> On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > >>> For my clock I am designing a module as I am not really a fan to use > >>> these types of old TTL logic. It's a 24 pin module that fits into a > >>> DIP24 IC socket. It basically mimics the 74141 but has high voltage > >>> output mosfets (240V) and the 4 inputs can be latched, so you don't > >>> need extra latches as required by the standard 74141. It also offers a > >>> blanking input, either by writing 0x0a or using a dedicated pin (which > >>> is convenient for PWM dimming). It can be interfaced with MCU or > >>> arduino. > >>> Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
I'm starting to get the impression that this is a parts-box project. Have you ever heard the expression that when the only tool you have is a hammer, everything starts looking like a nail? On 3/22/2012 11:42 AM, Imbanon wrote: Please take note that I am not using PNP's at all, only NPN's :) On Mar 22, 7:12 pm, Adam Jacobs wrote: _MUCH_ better. Okay, firstly this design can work - there's nothing fundamentally wrong with it. Like I said, you'll need to be able to make cathode-side blanking (74141) work if you're going to stick with only 3 anode drivers. 1) Your anode drivers aren't quite right. The resistor on the base of the NPN should be more like 10k (R1). You're missing the pulldown on the base as well. Add a 10k between the base of the NPN and GND. The resistor between the collector of the NPN and the base of the PNP should be more like 1M. The resistor between the base of the PNP and the collector of the PNP should be more like 10k. 2) The reason that you are getting current leakage with the 74141 is because your HV supply is too high. Instead of 215v, use 180v. -Adam On 3/22/2012 11:00 AM, Imbanon wrote: Sorry about that. I thought it was an universal shematic file type, 'cause they are all .sch Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729 Cheers On Mar 22, 4:14 pm, Adam Jacobswrote: Would you mind converting that schematic to some kind of image file? Is that an eaglecad file? blanking on the 74141 will cause leakage if the supply voltage is too high. Are you using real 74141's or the russian kind? From that picture, I'm not sure if that is leakage. -Adam On 3/22/2012 5:19 AM, Imbanon wrote: Hey all I found some time to make a schematic. It only shows the two 74141, nixie tubes and anode drivers. I also tried blanking nixies via 74141. I would have never guessed that you meant on hex code, as I am doing this on an arduino :) Blanking nixies with 74141's give me a lot of leaking (or at least I think thats leaking), so I'm not so sure about using this method. But I do think that it's maybe possible to divide the leaking to the rest of the nixies by adding a resistor for each anode, instead of sharing them. See for yourself in the links. http://www.mediafire.com/download.php?bbx4z4k5vjul56b http://www.mediafire.com/download.php?ym4s96yeusrm9sy So I guess my next move should be to remove the trimpots, and replace them with actual resistors for each anode. But what should I do with the blanking? To be honest, I would leave the setup as is, because it seems to work fine. But if you guys think I can do something better to get a longer tube life, I will make changes to the schematic immediately. Thanks! On Mar 19, 12:04 am, Dylan Distasio wrote: I'm very interested in hearing more about this module...Are you saying you are having this custom manufactured? If so, how have you found a way to do this economically? On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: For my clock I am designing a module as I am not really a fan to use these types of old TTL logic. It's a 24 pin module that fits into a DIP24 IC socket. It basically mimics the 74141 but has high voltage output mosfets (240V) and the 4 inputs can be latched, so you don't need extra latches as required by the standard 74141. It also offers a blanking input, either by writing 0x0a or using a dedicated pin (which is convenient for PWM dimming). It can be interfaced with MCU or arduino. Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Please take note that I am not using PNP's at all, only NPN's :) On Mar 22, 7:12 pm, Adam Jacobs wrote: > _MUCH_ better. > > Okay, firstly this design can work - there's nothing fundamentally wrong > with it. Like I said, you'll need to be able to make cathode-side > blanking (74141) work if you're going to stick with only 3 anode drivers. > > 1) Your anode drivers aren't quite right. The resistor on the base of > the NPN should be more like 10k (R1). You're missing the pulldown on the > base as well. Add a 10k between the base of the NPN and GND. The > resistor between the collector of the NPN and the base of the PNP should > be more like 1M. The resistor between the base of the PNP and the > collector of the PNP should be more like 10k. > > 2) The reason that you are getting current leakage with the 74141 is > because your HV supply is too high. Instead of 215v, use 180v. > > -Adam > > On 3/22/2012 11:00 AM, Imbanon wrote: > > > > > > > > > Sorry about that. I thought it was an universal shematic file type, > > 'cause they are all .sch > > > Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729 > > Cheers > > > On Mar 22, 4:14 pm, Adam Jacobs wrote: > >> Would you mind converting that schematic to some kind of image file? Is > >> that an eaglecad file? > > >> blanking on the 74141 will cause leakage if the supply voltage is too > >> high. Are you using real 74141's or the russian kind? > >> From that picture, I'm not sure if that is leakage. > > >> -Adam > > >> On 3/22/2012 5:19 AM, Imbanon wrote: > > >>> Hey all > >>> I found some time to make a schematic. It only shows the two 74141, > >>> nixie tubes and anode drivers. > >>> I also tried blanking nixies via 74141. I would have never guessed > >>> that you meant on hex code, as I am doing this on an arduino :) > >>> Blanking nixies with 74141's give me a lot of leaking (or at least I > >>> think thats leaking), so I'm not so sure about using this method. But > >>> I do think that it's maybe possible to divide the leaking to the rest > >>> of the nixies by adding a resistor for each anode, instead of sharing > >>> them. See for yourself in the links. > >>>http://www.mediafire.com/download.php?bbx4z4k5vjul56b > >>>http://www.mediafire.com/download.php?ym4s96yeusrm9sy > >>> So I guess my next move should be to remove the trimpots, and replace > >>> them with actual resistors for each anode. > >>> But what should I do with the blanking? To be honest, I would leave > >>> the setup as is, because it seems to work fine. But if you guys think > >>> I can do something better to get a longer tube life, I will make > >>> changes to the schematic immediately. > >>> Thanks! > >>> On Mar 19, 12:04 am, Dylan Distasio wrote: > I'm very interested in hearing more about this module...Are you saying > you > are having this custom manufactured? If so, how have you found a way to > do > this economically? > On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > > For my clock I am designing a module as I am not really a fan to use > > these types of old TTL logic. It's a 24 pin module that fits into a > > DIP24 IC socket. It basically mimics the 74141 but has high voltage > > output mosfets (240V) and the 4 inputs can be latched, so you don't > > need extra latches as required by the standard 74141. It also offers a > > blanking input, either by writing 0x0a or using a dedicated pin (which > > is convenient for PWM dimming). It can be interfaced with MCU or > > arduino. > > Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
_MUCH_ better. Okay, firstly this design can work - there's nothing fundamentally wrong with it. Like I said, you'll need to be able to make cathode-side blanking (74141) work if you're going to stick with only 3 anode drivers. 1) Your anode drivers aren't quite right. The resistor on the base of the NPN should be more like 10k (R1). You're missing the pulldown on the base as well. Add a 10k between the base of the NPN and GND. The resistor between the collector of the NPN and the base of the PNP should be more like 1M. The resistor between the base of the PNP and the collector of the PNP should be more like 10k. 2) The reason that you are getting current leakage with the 74141 is because your HV supply is too high. Instead of 215v, use 180v. -Adam On 3/22/2012 11:00 AM, Imbanon wrote: Sorry about that. I thought it was an universal shematic file type, 'cause they are all .sch Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729 Cheers On Mar 22, 4:14 pm, Adam Jacobs wrote: Would you mind converting that schematic to some kind of image file? Is that an eaglecad file? blanking on the 74141 will cause leakage if the supply voltage is too high. Are you using real 74141's or the russian kind? From that picture, I'm not sure if that is leakage. -Adam On 3/22/2012 5:19 AM, Imbanon wrote: Hey all I found some time to make a schematic. It only shows the two 74141, nixie tubes and anode drivers. I also tried blanking nixies via 74141. I would have never guessed that you meant on hex code, as I am doing this on an arduino :) Blanking nixies with 74141's give me a lot of leaking (or at least I think thats leaking), so I'm not so sure about using this method. But I do think that it's maybe possible to divide the leaking to the rest of the nixies by adding a resistor for each anode, instead of sharing them. See for yourself in the links. http://www.mediafire.com/download.php?bbx4z4k5vjul56b http://www.mediafire.com/download.php?ym4s96yeusrm9sy So I guess my next move should be to remove the trimpots, and replace them with actual resistors for each anode. But what should I do with the blanking? To be honest, I would leave the setup as is, because it seems to work fine. But if you guys think I can do something better to get a longer tube life, I will make changes to the schematic immediately. Thanks! On Mar 19, 12:04 am, Dylan Distasiowrote: I'm very interested in hearing more about this module...Are you saying you are having this custom manufactured? If so, how have you found a way to do this economically? On Sun, Mar 18, 2012 at 6:31 PM, Cobra007wrote: For my clock I am designing a module as I am not really a fan to use these types of old TTL logic. It's a 24 pin module that fits into a DIP24 IC socket. It basically mimics the 74141 but has high voltage output mosfets (240V) and the 4 inputs can be latched, so you don't need extra latches as required by the standard 74141. It also offers a blanking input, either by writing 0x0a or using a dedicated pin (which is convenient for PWM dimming). It can be interfaced with MCU or arduino. Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Sorry about that. I thought it was an universal shematic file type, 'cause they are all .sch Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729 Cheers On Mar 22, 4:14 pm, Adam Jacobs wrote: > Would you mind converting that schematic to some kind of image file? Is > that an eaglecad file? > > blanking on the 74141 will cause leakage if the supply voltage is too > high. Are you using real 74141's or the russian kind? > From that picture, I'm not sure if that is leakage. > > -Adam > > On 3/22/2012 5:19 AM, Imbanon wrote: > > > > > > > > > Hey all > > > I found some time to make a schematic. It only shows the two 74141, > > nixie tubes and anode drivers. > > I also tried blanking nixies via 74141. I would have never guessed > > that you meant on hex code, as I am doing this on an arduino :) > > Blanking nixies with 74141's give me a lot of leaking (or at least I > > think thats leaking), so I'm not so sure about using this method. But > > I do think that it's maybe possible to divide the leaking to the rest > > of the nixies by adding a resistor for each anode, instead of sharing > > them. See for yourself in the links. > > >http://www.mediafire.com/download.php?bbx4z4k5vjul56b > >http://www.mediafire.com/download.php?ym4s96yeusrm9sy > > > So I guess my next move should be to remove the trimpots, and replace > > them with actual resistors for each anode. > > But what should I do with the blanking? To be honest, I would leave > > the setup as is, because it seems to work fine. But if you guys think > > I can do something better to get a longer tube life, I will make > > changes to the schematic immediately. > > > Thanks! > > > On Mar 19, 12:04 am, Dylan Distasio wrote: > >> I'm very interested in hearing more about this module...Are you saying you > >> are having this custom manufactured? If so, how have you found a way to do > >> this economically? > > >> On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > > >>> For my clock I am designing a module as I am not really a fan to use > >>> these types of old TTL logic. It's a 24 pin module that fits into a > >>> DIP24 IC socket. It basically mimics the 74141 but has high voltage > >>> output mosfets (240V) and the 4 inputs can be latched, so you don't > >>> need extra latches as required by the standard 74141. It also offers a > >>> blanking input, either by writing 0x0a or using a dedicated pin (which > >>> is convenient for PWM dimming). It can be interfaced with MCU or > >>> arduino. > >>> Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
Would you mind converting that schematic to some kind of image file? Is that an eaglecad file? blanking on the 74141 will cause leakage if the supply voltage is too high. Are you using real 74141's or the russian kind? From that picture, I'm not sure if that is leakage. -Adam On 3/22/2012 5:19 AM, Imbanon wrote: Hey all I found some time to make a schematic. It only shows the two 74141, nixie tubes and anode drivers. I also tried blanking nixies via 74141. I would have never guessed that you meant on hex code, as I am doing this on an arduino :) Blanking nixies with 74141's give me a lot of leaking (or at least I think thats leaking), so I'm not so sure about using this method. But I do think that it's maybe possible to divide the leaking to the rest of the nixies by adding a resistor for each anode, instead of sharing them. See for yourself in the links. http://www.mediafire.com/download.php?bbx4z4k5vjul56b http://www.mediafire.com/download.php?ym4s96yeusrm9sy So I guess my next move should be to remove the trimpots, and replace them with actual resistors for each anode. But what should I do with the blanking? To be honest, I would leave the setup as is, because it seems to work fine. But if you guys think I can do something better to get a longer tube life, I will make changes to the schematic immediately. Thanks! On Mar 19, 12:04 am, Dylan Distasio wrote: I'm very interested in hearing more about this module...Are you saying you are having this custom manufactured? If so, how have you found a way to do this economically? On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: For my clock I am designing a module as I am not really a fan to use these types of old TTL logic. It's a 24 pin module that fits into a DIP24 IC socket. It basically mimics the 74141 but has high voltage output mosfets (240V) and the 4 inputs can be latched, so you don't need extra latches as required by the standard 74141. It also offers a blanking input, either by writing 0x0a or using a dedicated pin (which is convenient for PWM dimming). It can be interfaced with MCU or arduino. Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Could you share a few pics? Also, how much will they cost? :) On Mar 19, 2:33 am, Cobra007 wrote: > That should be fine Adam, I should have 50 modules in a couple of > weeks so I do have a few spares :-). > > Michel > > On Mar 19, 11:31 am, Adam Jacobs wrote: > > > > > > > > > I would be interested in this as well. Are you planning to market and > > sell these modules? > > > On 3/18/2012 4:19 PM, Cobra007 wrote: > > > > Hi Dylan, > > > > It is actually a small circuit board that I have manufactured together > > > with the nixie watch circuit boards to save costs. The circuit board > > > is the size of a DIP24 chip and has an SMD 4514 multiplexer that > > > drives 10 high voltage SMD mosfets. There is 1 spare mosfet on the > > > board that is not driven by the multiplexer, it can be used to drive > > > the colon lamps for example, not really a dedicated purpose but I had > > > board space left over :-). It's pretty basic really, but very > > > convenient to use. > > > > Michel > > > > On Mar 19, 10:04 am, Dylan Distasio wrote: > > >> I'm very interested in hearing more about this module...Are you saying > > >> you > > >> are having this custom manufactured? If so, how have you found a way to > > >> do > > >> this economically? > > > >> On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > > > >>> For my clock I am designing a module as I am not really a fan to use > > >>> these types of old TTL logic. It's a 24 pin module that fits into a > > >>> DIP24 IC socket. It basically mimics the 74141 but has high voltage > > >>> output mosfets (240V) and the 4 inputs can be latched, so you don't > > >>> need extra latches as required by the standard 74141. It also offers a > > >>> blanking input, either by writing 0x0a or using a dedicated pin (which > > >>> is convenient for PWM dimming). It can be interfaced with MCU or > > >>> arduino. > > >>> Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Hey all I found some time to make a schematic. It only shows the two 74141, nixie tubes and anode drivers. I also tried blanking nixies via 74141. I would have never guessed that you meant on hex code, as I am doing this on an arduino :) Blanking nixies with 74141's give me a lot of leaking (or at least I think thats leaking), so I'm not so sure about using this method. But I do think that it's maybe possible to divide the leaking to the rest of the nixies by adding a resistor for each anode, instead of sharing them. See for yourself in the links. http://www.mediafire.com/download.php?bbx4z4k5vjul56b http://www.mediafire.com/download.php?ym4s96yeusrm9sy So I guess my next move should be to remove the trimpots, and replace them with actual resistors for each anode. But what should I do with the blanking? To be honest, I would leave the setup as is, because it seems to work fine. But if you guys think I can do something better to get a longer tube life, I will make changes to the schematic immediately. Thanks! On Mar 19, 12:04 am, Dylan Distasio wrote: > I'm very interested in hearing more about this module...Are you saying you > are having this custom manufactured? If so, how have you found a way to do > this economically? > > > > > > > > On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > > > For my clock I am designing a module as I am not really a fan to use > > these types of old TTL logic. It's a 24 pin module that fits into a > > DIP24 IC socket. It basically mimics the 74141 but has high voltage > > output mosfets (240V) and the 4 inputs can be latched, so you don't > > need extra latches as required by the standard 74141. It also offers a > > blanking input, either by writing 0x0a or using a dedicated pin (which > > is convenient for PWM dimming). It can be interfaced with MCU or > > arduino. > > > Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
That should be fine Adam, I should have 50 modules in a couple of weeks so I do have a few spares :-). Michel On Mar 19, 11:31 am, Adam Jacobs wrote: > I would be interested in this as well. Are you planning to market and > sell these modules? > > On 3/18/2012 4:19 PM, Cobra007 wrote: > > > > > > > > > Hi Dylan, > > > It is actually a small circuit board that I have manufactured together > > with the nixie watch circuit boards to save costs. The circuit board > > is the size of a DIP24 chip and has an SMD 4514 multiplexer that > > drives 10 high voltage SMD mosfets. There is 1 spare mosfet on the > > board that is not driven by the multiplexer, it can be used to drive > > the colon lamps for example, not really a dedicated purpose but I had > > board space left over :-). It's pretty basic really, but very > > convenient to use. > > > Michel > > > On Mar 19, 10:04 am, Dylan Distasio wrote: > >> I'm very interested in hearing more about this module...Are you saying you > >> are having this custom manufactured? If so, how have you found a way to do > >> this economically? > > >> On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > > >>> For my clock I am designing a module as I am not really a fan to use > >>> these types of old TTL logic. It's a 24 pin module that fits into a > >>> DIP24 IC socket. It basically mimics the 74141 but has high voltage > >>> output mosfets (240V) and the 4 inputs can be latched, so you don't > >>> need extra latches as required by the standard 74141. It also offers a > >>> blanking input, either by writing 0x0a or using a dedicated pin (which > >>> is convenient for PWM dimming). It can be interfaced with MCU or > >>> arduino. > >>> Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
I would be interested in this as well. Are you planning to market and sell these modules? On 3/18/2012 4:19 PM, Cobra007 wrote: Hi Dylan, It is actually a small circuit board that I have manufactured together with the nixie watch circuit boards to save costs. The circuit board is the size of a DIP24 chip and has an SMD 4514 multiplexer that drives 10 high voltage SMD mosfets. There is 1 spare mosfet on the board that is not driven by the multiplexer, it can be used to drive the colon lamps for example, not really a dedicated purpose but I had board space left over :-). It's pretty basic really, but very convenient to use. Michel On Mar 19, 10:04 am, Dylan Distasio wrote: I'm very interested in hearing more about this module...Are you saying you are having this custom manufactured? If so, how have you found a way to do this economically? On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: For my clock I am designing a module as I am not really a fan to use these types of old TTL logic. It's a 24 pin module that fits into a DIP24 IC socket. It basically mimics the 74141 but has high voltage output mosfets (240V) and the 4 inputs can be latched, so you don't need extra latches as required by the standard 74141. It also offers a blanking input, either by writing 0x0a or using a dedicated pin (which is convenient for PWM dimming). It can be interfaced with MCU or arduino. Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Hi Dylan, It is actually a small circuit board that I have manufactured together with the nixie watch circuit boards to save costs. The circuit board is the size of a DIP24 chip and has an SMD 4514 multiplexer that drives 10 high voltage SMD mosfets. There is 1 spare mosfet on the board that is not driven by the multiplexer, it can be used to drive the colon lamps for example, not really a dedicated purpose but I had board space left over :-). It's pretty basic really, but very convenient to use. Michel On Mar 19, 10:04 am, Dylan Distasio wrote: > I'm very interested in hearing more about this module...Are you saying you > are having this custom manufactured? If so, how have you found a way to do > this economically? > > > > > > > > On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > > > For my clock I am designing a module as I am not really a fan to use > > these types of old TTL logic. It's a 24 pin module that fits into a > > DIP24 IC socket. It basically mimics the 74141 but has high voltage > > output mosfets (240V) and the 4 inputs can be latched, so you don't > > need extra latches as required by the standard 74141. It also offers a > > blanking input, either by writing 0x0a or using a dedicated pin (which > > is convenient for PWM dimming). It can be interfaced with MCU or > > arduino. > > > Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
I'm very interested in hearing more about this module...Are you saying you are having this custom manufactured? If so, how have you found a way to do this economically? On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote: > > > For my clock I am designing a module as I am not really a fan to use > these types of old TTL logic. It's a 24 pin module that fits into a > DIP24 IC socket. It basically mimics the 74141 but has high voltage > output mosfets (240V) and the 4 inputs can be latched, so you don't > need extra latches as required by the standard 74141. It also offers a > blanking input, either by writing 0x0a or using a dedicated pin (which > is convenient for PWM dimming). It can be interfaced with MCU or > arduino. > > Michel > > > > > > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
I'd start with 6.8K anode resistors (assuming 3,6 to 7.3 is your target range) and see how it works out. Keep a close eye on it for a couple of months, if its running 24/7. If the current is too low, you'll start to see partial illumination on the the digits over time. Then you need to increase the current. Its easier to do this by tacking resistors in parallel, to existing resistors, than by complete replacing resistors. On 74141s any code over 9 will keep all cathodes OFF. So, you can blank it that way. There is a possibility of leakage as the parts age. This will show as "ghosting". Again, this may not show up right away. Only time will tell. Since you're already switching the anodes, why not use the anode circuit to blank the display. Its only a software modification. Also, since you're muxing, the supply voltage will be higher. Nominally 200V, so any leakage problems, will show up earlier. On Sunday, March 18, 2012 3:31:22 PM UTC-7, Cobra007 wrote: > > If you take 7.3k resistors rather than 3.65k resistors, the tubes will > only be 6dB less bright which is not significant. If that increases > tube life, I would say, that is the better choice as you pointed out > already. > > For blanking, I think Adam means to send a hex number (0x0A) to the > 74141 (D=1; C=0; B=1; A=0). According to the datasheet, this would > lead to a correct blanking of the tubes. > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/7s_AhKwZ5TQJ. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
If you take 7.3k resistors rather than 3.65k resistors, the tubes will only be 6dB less bright which is not significant. If that increases tube life, I would say, that is the better choice as you pointed out already. For blanking, I think Adam means to send a hex number (0x0A) to the 74141 (D=1; C=0; B=1; A=0). According to the datasheet, this would lead to a correct blanking of the tubes. For my clock I am designing a module as I am not really a fan to use these types of old TTL logic. It's a 24 pin module that fits into a DIP24 IC socket. It basically mimics the 74141 but has high voltage output mosfets (240V) and the 4 inputs can be latched, so you don't need extra latches as required by the standard 74141. It also offers a blanking input, either by writing 0x0a or using a dedicated pin (which is convenient for PWM dimming). It can be interfaced with MCU or arduino. Michel On Mar 19, 6:21 am, Imbanon wrote: > Hey Cobra! Thanks you for your explanation. I see what you did there, > and you are quite correct. But the thing is that I did not calculate > anything using power. You are completely right with the brightness, > but I do not want the same brightness as with direct drived nixies. I > lean towards tube life, and I think that the only way to achieve this > is by getting the correct current, and that would be around 2mA. > > I will make a schematic and share it, hopefully tomorrow, if I find > some time. > > My first design was 1x6, but I wasn't happy with the brightness. It > also required some higher current peaks, which can't be good for the > tubes. 2x3 mux design gives better brightness, but uses one more pin. > > And can someone please explain how does one blank a 74141? Adam, what > do you mean by setting the input to A? Setting a logic 1 to the A > input pin by the datasheet? That only sets the output to "1". My > design so far didn't use blanking with the 74141's. I just turned all > anodes off for 200us, and I never had any ghosting problems or > anything like that. > > Cheers > > On Mar 17, 6:35 am, Cobra007 wrote: > > > > > > > > > Hi Imbanon, > > > I followed your calculations for quite a bit and was also wondering > > why your measurements are so much different than your calculations. My > > calculation suggest that you need a 7.3k resistor for each tube. This > > means if you have 2 tubes with a common anode connected to 1 resistor, > > and switch both tubes on at the same time (which you say you do), then > > you need to half the resistor. In that case, 3.65k. > > > Now, I was also puzzled why my resistor calculation results in half of > > your resistor calculation. The answer is in fact quite simple, and I > > will try to explain to you. > > > First of all, we need to agree that the tube power needs to be the > > same in both direct drive as well as multiplexed mode to guarantee > > equal tube brightness. Therefore Pdc = Prms > > > Pdc = Udc * Idc > > and also > > Prms = Urms * Irms > > > Do you notice the problem already? > > > Pdc = 145V * 2mA = 0.29W > > > Prms = 145*sqrt(T1/T) * Irms > > > So, Irms should be 0.29 / Urms = 0.29 / (145*sqrt(T1/T)) = 3.9mA > > > Your calculation was based on the fact that Irms had to be 2mA, but > > this is not correct because it needs to be 3.9mA. > > The peak current through the resistor is then 3.9mA / sqrt(T1/T) = > > 7.5mA per tube (15mA if 2 tubes are switched on at the same time). > > This is exactly what you get if you take the average currents. You > > want 12mA average current (6 tubes * 2mA). which is 12mA / (26.7 / > > 33.3) = 15mA. > > > Unknowingly, to calculate Prms you were multiplying Irms * Udc, not > > Irms * Urms. > > > Does this make sense? > > > I do agree with the rest of the guys that 6 resistors (7.3k) would be > > better that 3 resistors (3.65k), it will split the current more evenly > > through the 2 tubes. > > > Michel > > > On Mar 17, 6:18 am, Imbanon wrote: > > > > First of all, thank you all for your support. Feels great to have some > > > people with knowledge behind my back. > > > So many replies since I had time to check the group last time that I > > > don't know where to start :) > > > > I do not have a schematic for my design, as it is my own design that I > > > pretty much pull out of my head as I go. That often shown like a bad > > > idea, making me to change a lot of things afterwards. Just like today, > > > I had to rewire the whole 'spider web'. And that was the second time I > > > had to do it! > > > And I have to clear out that I have a common anode resistor for 2 > > > tubes, making a total of 3 anode resistors for all 6 tubes. That means > > > that the current has to be double (resistance cut by half). I hope > > > that it now explains the rounded 8mA (7.74 to be more precise) on the > > > anode resistor. It cuts to two nixies, giving appox 3.87mA peak > > > current to each tube. So then 3.87*sqrt(0.267)=2mA RMS > > > Anyhow, I do believe that I have to use the RMS values when working > > > w
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Hey Cobra! Thanks you for your explanation. I see what you did there, and you are quite correct. But the thing is that I did not calculate anything using power. You are completely right with the brightness, but I do not want the same brightness as with direct drived nixies. I lean towards tube life, and I think that the only way to achieve this is by getting the correct current, and that would be around 2mA. I will make a schematic and share it, hopefully tomorrow, if I find some time. My first design was 1x6, but I wasn't happy with the brightness. It also required some higher current peaks, which can't be good for the tubes. 2x3 mux design gives better brightness, but uses one more pin. And can someone please explain how does one blank a 74141? Adam, what do you mean by setting the input to A? Setting a logic 1 to the A input pin by the datasheet? That only sets the output to "1". My design so far didn't use blanking with the 74141's. I just turned all anodes off for 200us, and I never had any ghosting problems or anything like that. Cheers On Mar 17, 6:35 am, Cobra007 wrote: > Hi Imbanon, > > I followed your calculations for quite a bit and was also wondering > why your measurements are so much different than your calculations. My > calculation suggest that you need a 7.3k resistor for each tube. This > means if you have 2 tubes with a common anode connected to 1 resistor, > and switch both tubes on at the same time (which you say you do), then > you need to half the resistor. In that case, 3.65k. > > Now, I was also puzzled why my resistor calculation results in half of > your resistor calculation. The answer is in fact quite simple, and I > will try to explain to you. > > First of all, we need to agree that the tube power needs to be the > same in both direct drive as well as multiplexed mode to guarantee > equal tube brightness. Therefore Pdc = Prms > > Pdc = Udc * Idc > and also > Prms = Urms * Irms > > Do you notice the problem already? > > Pdc = 145V * 2mA = 0.29W > > Prms = 145*sqrt(T1/T) * Irms > > So, Irms should be 0.29 / Urms = 0.29 / (145*sqrt(T1/T)) = 3.9mA > > Your calculation was based on the fact that Irms had to be 2mA, but > this is not correct because it needs to be 3.9mA. > The peak current through the resistor is then 3.9mA / sqrt(T1/T) = > 7.5mA per tube (15mA if 2 tubes are switched on at the same time). > This is exactly what you get if you take the average currents. You > want 12mA average current (6 tubes * 2mA). which is 12mA / (26.7 / > 33.3) = 15mA. > > Unknowingly, to calculate Prms you were multiplying Irms * Udc, not > Irms * Urms. > > Does this make sense? > > I do agree with the rest of the guys that 6 resistors (7.3k) would be > better that 3 resistors (3.65k), it will split the current more evenly > through the 2 tubes. > > Michel > > On Mar 17, 6:18 am, Imbanon wrote: > > > > > > > > > First of all, thank you all for your support. Feels great to have some > > people with knowledge behind my back. > > So many replies since I had time to check the group last time that I > > don't know where to start :) > > > I do not have a schematic for my design, as it is my own design that I > > pretty much pull out of my head as I go. That often shown like a bad > > idea, making me to change a lot of things afterwards. Just like today, > > I had to rewire the whole 'spider web'. And that was the second time I > > had to do it! > > And I have to clear out that I have a common anode resistor for 2 > > tubes, making a total of 3 anode resistors for all 6 tubes. That means > > that the current has to be double (resistance cut by half). I hope > > that it now explains the rounded 8mA (7.74 to be more precise) on the > > anode resistor. It cuts to two nixies, giving appox 3.87mA peak > > current to each tube. So then 3.87*sqrt(0.267)=2mA RMS > > Anyhow, I do believe that I have to use the RMS values when working > > with multiplexed designs, rather than average. Just like someone > > already explained why, because of the power dissipation. I really hope > > it is that way :) > > > Well that's all for now. I hope that my setup with anode resistors is > > finally done. If not - I still have another week to use all the fancy > > expensive oscilloscopes! So if anyone doesn't agree with this, please > > say the word :) > > > Cheers > > > On Mar 16, 9:13 am, Dekatron42 wrote: > > > > Many manufacturers write that you will have to contact them for the > > > special curves you need when you are going to multiplex their Nixies > > > since they do not usually print that information in the databooks. > > > > These sheets show you that the Nixie will have an increased turn-on > > > voltage corresponding to the increased current when run in switched > > > mode. This is the same as when a neon voltage stabilizer tube is used, > > > the voltage increases somewhat when the current increases, you can > > > check the OB2 voltage regulator tube for instance. > > > > The curves for most Nixies when
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Hi Imbanon, I followed your calculations for quite a bit and was also wondering why your measurements are so much different than your calculations. My calculation suggest that you need a 7.3k resistor for each tube. This means if you have 2 tubes with a common anode connected to 1 resistor, and switch both tubes on at the same time (which you say you do), then you need to half the resistor. In that case, 3.65k. Now, I was also puzzled why my resistor calculation results in half of your resistor calculation. The answer is in fact quite simple, and I will try to explain to you. First of all, we need to agree that the tube power needs to be the same in both direct drive as well as multiplexed mode to guarantee equal tube brightness. Therefore Pdc = Prms Pdc = Udc * Idc and also Prms = Urms * Irms Do you notice the problem already? Pdc = 145V * 2mA = 0.29W Prms = 145*sqrt(T1/T) * Irms So, Irms should be 0.29 / Urms = 0.29 / (145*sqrt(T1/T)) = 3.9mA Your calculation was based on the fact that Irms had to be 2mA, but this is not correct because it needs to be 3.9mA. The peak current through the resistor is then 3.9mA / sqrt(T1/T) = 7.5mA per tube (15mA if 2 tubes are switched on at the same time). This is exactly what you get if you take the average currents. You want 12mA average current (6 tubes * 2mA). which is 12mA / (26.7 / 33.3) = 15mA. Unknowingly, to calculate Prms you were multiplying Irms * Udc, not Irms * Urms. Does this make sense? I do agree with the rest of the guys that 6 resistors (7.3k) would be better that 3 resistors (3.65k), it will split the current more evenly through the 2 tubes. Michel On Mar 17, 6:18 am, Imbanon wrote: > First of all, thank you all for your support. Feels great to have some > people with knowledge behind my back. > So many replies since I had time to check the group last time that I > don't know where to start :) > > I do not have a schematic for my design, as it is my own design that I > pretty much pull out of my head as I go. That often shown like a bad > idea, making me to change a lot of things afterwards. Just like today, > I had to rewire the whole 'spider web'. And that was the second time I > had to do it! > And I have to clear out that I have a common anode resistor for 2 > tubes, making a total of 3 anode resistors for all 6 tubes. That means > that the current has to be double (resistance cut by half). I hope > that it now explains the rounded 8mA (7.74 to be more precise) on the > anode resistor. It cuts to two nixies, giving appox 3.87mA peak > current to each tube. So then 3.87*sqrt(0.267)=2mA RMS > Anyhow, I do believe that I have to use the RMS values when working > with multiplexed designs, rather than average. Just like someone > already explained why, because of the power dissipation. I really hope > it is that way :) > > Well that's all for now. I hope that my setup with anode resistors is > finally done. If not - I still have another week to use all the fancy > expensive oscilloscopes! So if anyone doesn't agree with this, please > say the word :) > > Cheers > > On Mar 16, 9:13 am, Dekatron42 wrote: > > > > > > > > > Many manufacturers write that you will have to contact them for the > > special curves you need when you are going to multiplex their Nixies > > since they do not usually print that information in the databooks. > > > These sheets show you that the Nixie will have an increased turn-on > > voltage corresponding to the increased current when run in switched > > mode. This is the same as when a neon voltage stabilizer tube is used, > > the voltage increases somewhat when the current increases, you can > > check the OB2 voltage regulator tube for instance. > > > The curves for most Nixies when used in multiplexed mode are not > > linear so if you can't find those curves you'll have to make the > > measurements yourself and take into account the spread between > > different Nixies to draw the curve. Some of these special curves have > > a voltage span of approximately 10-30V for a certain current through > > the Nixie, so there is an upper and a lower limit for the turn-on > > voltage corresponding to the current used. > > > This book:http://www.oldtimeradio.de/BU7908.php"Electronica 171 - > > Elektronische Anzeigebauelemente" by Winfired Müller contains a few of > > these curves for the ZM-series of Nixies. > > > /Martin > > > On 16 mar, 00:55, Cobra007 wrote: > > > > Yes, I think I mentioned "slightly" increase rather than a mayor > > > increase. > > > > I have measure this on another nixie tube and came to the following > > > voltages: > > > 0.5mA : 120V > > > 1.0mA : 125V > > > 1.5mA: 130V > > > 2.0mA: 133V > > > 3.0mA: 140V > > > 4.5mA: 150V > > > > His tube current will increase from 2mA to about 7.5mA, so according > > > to the above measurements, the increase in tube voltage will be > > > playing a role. > > > > Michel > > > > On Mar 16, 10:06 am, Charles MacDonald wrote: > > > > > On 12-03-15 05:46 AM, Cobra
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
I wasn't home at the time, and all I had were three 10k trimpots :) Why is that bad? I would leave it that way, if that's ok. On Mar 16, 8:27 pm, Adam Jacobs wrote: > Why are you sharing 1 anode resistor across two tubes? :) Is board space > at that much of a premium? > > On 3/16/2012 12:18 PM, Imbanon wrote: > > > > > > > > > First of all, thank you all for your support. Feels great to have some > > people with knowledge behind my back. > > So many replies since I had time to check the group last time that I > > don't know where to start :) > > > I do not have a schematic for my design, as it is my own design that I > > pretty much pull out of my head as I go. That often shown like a bad > > idea, making me to change a lot of things afterwards. Just like today, > > I had to rewire the whole 'spider web'. And that was the second time I > > had to do it! > > And I have to clear out that I have a common anode resistor for 2 > > tubes, making a total of 3 anode resistors for all 6 tubes. That means > > that the current has to be double (resistance cut by half). I hope > > that it now explains the rounded 8mA (7.74 to be more precise) on the > > anode resistor. It cuts to two nixies, giving appox 3.87mA peak > > current to each tube. So then 3.87*sqrt(0.267)=2mA RMS > > Anyhow, I do believe that I have to use the RMS values when working > > with multiplexed designs, rather than average. Just like someone > > already explained why, because of the power dissipation. I really hope > > it is that way :) > > > Well that's all for now. I hope that my setup with anode resistors is > > finally done. If not - I still have another week to use all the fancy > > expensive oscilloscopes! So if anyone doesn't agree with this, please > > say the word :) > > > Cheers > > > On Mar 16, 9:13 am, Dekatron42 wrote: > >> Many manufacturers write that you will have to contact them for the > >> special curves you need when you are going to multiplex their Nixies > >> since they do not usually print that information in the databooks. > > >> These sheets show you that the Nixie will have an increased turn-on > >> voltage corresponding to the increased current when run in switched > >> mode. This is the same as when a neon voltage stabilizer tube is used, > >> the voltage increases somewhat when the current increases, you can > >> check the OB2 voltage regulator tube for instance. > > >> The curves for most Nixies when used in multiplexed mode are not > >> linear so if you can't find those curves you'll have to make the > >> measurements yourself and take into account the spread between > >> different Nixies to draw the curve. Some of these special curves have > >> a voltage span of approximately 10-30V for a certain current through > >> the Nixie, so there is an upper and a lower limit for the turn-on > >> voltage corresponding to the current used. > > >> This book:http://www.oldtimeradio.de/BU7908.php"Electronica 171 - > >> Elektronische Anzeigebauelemente" by Winfired M�ller contains a few of > >> these curves for the ZM-series of Nixies. > > >> /Martin > > >> On 16 mar, 00:55, Cobra007 wrote: > > >>> Yes, I think I mentioned "slightly" increase rather than a mayor > >>> increase. > >>> I have measure this on another nixie tube and came to the following > >>> voltages: > >>> 0.5mA : 120V > >>> 1.0mA : 125V > >>> 1.5mA: 130V > >>> 2.0mA: 133V > >>> 3.0mA: 140V > >>> 4.5mA: 150V > >>> His tube current will increase from 2mA to about 7.5mA, so according > >>> to the above measurements, the increase in tube voltage will be > >>> playing a role. > >>> Michel > >>> On Mar 16, 10:06 am, Charles MacDonald wrote: > On 12-03-15 05:46 AM, Cobra007 wrote: > > So it looks like your resistor is correct. The only thing is that the > > voltage across the tube will slightly increase due to the higher > > current, so it's not 100% correct but pretty much. > Since we are talking a Neon device, the voltage across the tube will try > to stay the same, with the current adjusting if needed. That is why > Neon bulbs were used as Voltage reference devices in days of Old. > -- > Charles MacDonald Stittsville Ontario > cm...@zeusprune.ca Just Beyond the > Fringehttp://users.trytel.com/~cmacd/tubes.html > No Microsoft Products were used in sending this e-mail. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
Why are you sharing 1 anode resistor across two tubes? :) Is board space at that much of a premium? On 3/16/2012 12:18 PM, Imbanon wrote: First of all, thank you all for your support. Feels great to have some people with knowledge behind my back. So many replies since I had time to check the group last time that I don't know where to start :) I do not have a schematic for my design, as it is my own design that I pretty much pull out of my head as I go. That often shown like a bad idea, making me to change a lot of things afterwards. Just like today, I had to rewire the whole 'spider web'. And that was the second time I had to do it! And I have to clear out that I have a common anode resistor for 2 tubes, making a total of 3 anode resistors for all 6 tubes. That means that the current has to be double (resistance cut by half). I hope that it now explains the rounded 8mA (7.74 to be more precise) on the anode resistor. It cuts to two nixies, giving appox 3.87mA peak current to each tube. So then 3.87*sqrt(0.267)=2mA RMS Anyhow, I do believe that I have to use the RMS values when working with multiplexed designs, rather than average. Just like someone already explained why, because of the power dissipation. I really hope it is that way :) Well that's all for now. I hope that my setup with anode resistors is finally done. If not - I still have another week to use all the fancy expensive oscilloscopes! So if anyone doesn't agree with this, please say the word :) Cheers On Mar 16, 9:13 am, Dekatron42 wrote: Many manufacturers write that you will have to contact them for the special curves you need when you are going to multiplex their Nixies since they do not usually print that information in the databooks. These sheets show you that the Nixie will have an increased turn-on voltage corresponding to the increased current when run in switched mode. This is the same as when a neon voltage stabilizer tube is used, the voltage increases somewhat when the current increases, you can check the OB2 voltage regulator tube for instance. The curves for most Nixies when used in multiplexed mode are not linear so if you can't find those curves you'll have to make the measurements yourself and take into account the spread between different Nixies to draw the curve. Some of these special curves have a voltage span of approximately 10-30V for a certain current through the Nixie, so there is an upper and a lower limit for the turn-on voltage corresponding to the current used. This book:http://www.oldtimeradio.de/BU7908.php"Electronica 171 - Elektronische Anzeigebauelemente" by Winfired Müller contains a few of these curves for the ZM-series of Nixies. /Martin On 16 mar, 00:55, Cobra007 wrote: Yes, I think I mentioned "slightly" increase rather than a mayor increase. I have measure this on another nixie tube and came to the following voltages: 0.5mA : 120V 1.0mA : 125V 1.5mA: 130V 2.0mA: 133V 3.0mA: 140V 4.5mA: 150V His tube current will increase from 2mA to about 7.5mA, so according to the above measurements, the increase in tube voltage will be playing a role. Michel On Mar 16, 10:06 am, Charles MacDonald wrote: On 12-03-15 05:46 AM, Cobra007 wrote: So it looks like your resistor is correct. The only thing is that the voltage across the tube will slightly increase due to the higher current, so it's not 100% correct but pretty much. Since we are talking a Neon device, the voltage across the tube will try to stay the same, with the current adjusting if needed. That is why Neon bulbs were used as Voltage reference devices in days of Old. -- Charles MacDonald Stittsville Ontario cm...@zeusprune.ca Just Beyond the Fringehttp://users.trytel.com/~cmacd/tubes.html No Microsoft Products were used in sending this e-mail. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Oh and I accidentaly reported your post as spam. Sorry about that! Dunno how that effects anything though.. On Mar 16, 9:13 am, Dekatron42 wrote: > Many manufacturers write that you will have to contact them for the > special curves you need when you are going to multiplex their Nixies > since they do not usually print that information in the databooks. > > These sheets show you that the Nixie will have an increased turn-on > voltage corresponding to the increased current when run in switched > mode. This is the same as when a neon voltage stabilizer tube is used, > the voltage increases somewhat when the current increases, you can > check the OB2 voltage regulator tube for instance. > > The curves for most Nixies when used in multiplexed mode are not > linear so if you can't find those curves you'll have to make the > measurements yourself and take into account the spread between > different Nixies to draw the curve. Some of these special curves have > a voltage span of approximately 10-30V for a certain current through > the Nixie, so there is an upper and a lower limit for the turn-on > voltage corresponding to the current used. > > This book:http://www.oldtimeradio.de/BU7908.php"Electronica 171 - > Elektronische Anzeigebauelemente" by Winfired Müller contains a few of > these curves for the ZM-series of Nixies. > > /Martin > > On 16 mar, 00:55, Cobra007 wrote: > > > > > > > > > Yes, I think I mentioned "slightly" increase rather than a mayor > > increase. > > > I have measure this on another nixie tube and came to the following > > voltages: > > 0.5mA : 120V > > 1.0mA : 125V > > 1.5mA: 130V > > 2.0mA: 133V > > 3.0mA: 140V > > 4.5mA: 150V > > > His tube current will increase from 2mA to about 7.5mA, so according > > to the above measurements, the increase in tube voltage will be > > playing a role. > > > Michel > > > On Mar 16, 10:06 am, Charles MacDonald wrote: > > > > On 12-03-15 05:46 AM, Cobra007 wrote: > > > > > So it looks like your resistor is correct. The only thing is that the > > > > voltage across the tube will slightly increase due to the higher > > > > current, so it's not 100% correct but pretty much. > > > > Since we are talking a Neon device, the voltage across the tube will try > > > to stay the same, with the current adjusting if needed. That is why > > > Neon bulbs were used as Voltage reference devices in days of Old. > > > > -- > > > Charles MacDonald Stittsville Ontario > > > cm...@zeusprune.ca Just Beyond the > > > Fringehttp://users.trytel.com/~cmacd/tubes.html > > > No Microsoft Products were used in sending this e-mail. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
First of all, thank you all for your support. Feels great to have some people with knowledge behind my back. So many replies since I had time to check the group last time that I don't know where to start :) I do not have a schematic for my design, as it is my own design that I pretty much pull out of my head as I go. That often shown like a bad idea, making me to change a lot of things afterwards. Just like today, I had to rewire the whole 'spider web'. And that was the second time I had to do it! And I have to clear out that I have a common anode resistor for 2 tubes, making a total of 3 anode resistors for all 6 tubes. That means that the current has to be double (resistance cut by half). I hope that it now explains the rounded 8mA (7.74 to be more precise) on the anode resistor. It cuts to two nixies, giving appox 3.87mA peak current to each tube. So then 3.87*sqrt(0.267)=2mA RMS Anyhow, I do believe that I have to use the RMS values when working with multiplexed designs, rather than average. Just like someone already explained why, because of the power dissipation. I really hope it is that way :) Well that's all for now. I hope that my setup with anode resistors is finally done. If not - I still have another week to use all the fancy expensive oscilloscopes! So if anyone doesn't agree with this, please say the word :) Cheers On Mar 16, 9:13 am, Dekatron42 wrote: > Many manufacturers write that you will have to contact them for the > special curves you need when you are going to multiplex their Nixies > since they do not usually print that information in the databooks. > > These sheets show you that the Nixie will have an increased turn-on > voltage corresponding to the increased current when run in switched > mode. This is the same as when a neon voltage stabilizer tube is used, > the voltage increases somewhat when the current increases, you can > check the OB2 voltage regulator tube for instance. > > The curves for most Nixies when used in multiplexed mode are not > linear so if you can't find those curves you'll have to make the > measurements yourself and take into account the spread between > different Nixies to draw the curve. Some of these special curves have > a voltage span of approximately 10-30V for a certain current through > the Nixie, so there is an upper and a lower limit for the turn-on > voltage corresponding to the current used. > > This book:http://www.oldtimeradio.de/BU7908.php"Electronica 171 - > Elektronische Anzeigebauelemente" by Winfired Müller contains a few of > these curves for the ZM-series of Nixies. > > /Martin > > On 16 mar, 00:55, Cobra007 wrote: > > > > > > > > > Yes, I think I mentioned "slightly" increase rather than a mayor > > increase. > > > I have measure this on another nixie tube and came to the following > > voltages: > > 0.5mA : 120V > > 1.0mA : 125V > > 1.5mA: 130V > > 2.0mA: 133V > > 3.0mA: 140V > > 4.5mA: 150V > > > His tube current will increase from 2mA to about 7.5mA, so according > > to the above measurements, the increase in tube voltage will be > > playing a role. > > > Michel > > > On Mar 16, 10:06 am, Charles MacDonald wrote: > > > > On 12-03-15 05:46 AM, Cobra007 wrote: > > > > > So it looks like your resistor is correct. The only thing is that the > > > > voltage across the tube will slightly increase due to the higher > > > > current, so it's not 100% correct but pretty much. > > > > Since we are talking a Neon device, the voltage across the tube will try > > > to stay the same, with the current adjusting if needed. That is why > > > Neon bulbs were used as Voltage reference devices in days of Old. > > > > -- > > > Charles MacDonald Stittsville Ontario > > > cm...@zeusprune.ca Just Beyond the > > > Fringehttp://users.trytel.com/~cmacd/tubes.html > > > No Microsoft Products were used in sending this e-mail. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
> What would the reason be to choose for a higher voltage rather than a > lower anode resistor? You can achieve a higher tube current by either > raising the voltage or lowering the resistor, so what is the advantage > of raising the voltage? Is it because ionization will be quicker or > doesn't have that anything to do with it? Ionization will be quicker with a higher voltage. Mike M. (threeneurons) actually went to the trouble to measure the turn-on behaviour of a nixie: http://threeneurons.files.wordpress.com/2011/08/timing01.jpg I'm thinking of duplicating his setup and trying it with different anode voltages and a few different nixies (I'm guessing little nixies ionize faster). I may also try using a decimal point as a "primer" and even comparing nixies with and without ambient light. Another advantage of higher voltage is better current regulation - since more of the drop is across the anode resistor and less across the (dynamic, negative, varies with the digit lit) resistance of the nixie, the current for different digits will be more similar. A disadvantage of higher voltage is lower efficiency - more of your voltage is used up in the anode resistors as heat. This can be combated by using a current-limited supply, which can give wonderful efficiency but adds a good deal of complexity (current limiting a negative resistance load which is being continually switched ain't easy). Alternatively, a scheme like David uses in his watches (raising the voltage to strike, then lowering it) strikes a different balance between ionization time, efficiency, and complexity. Another disadvantage is the voltage impressed on the "off" cathodes if the anode voltage is turned on but the digit is blanked. This can lead to ghosting (especially if the transistors are zener clamped or leak at high voltage) or failure of the cathode switches if they can't withstand the voltage. An obvious way to address this is don't enable the anode switch for blanked digits, which requires a few wiring and/or software considerations, depending on the design. - John -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
It all has to do with how you design the circuit around the Nixie, in the old days the transistors did not have perhaps more than 120V Vce as a maximum, usually lower than that, around 80-100V. With a lower Vce you have to use either a cathode bias voltage to meet the transistor requirements or youll have to use both a positive and negative voltage to get the bias which the transistor would work with. Then if you lower the resistor or raise the voltage is up to what you want to achieve and what transistors you have at hand. It also has to do with what turn-on time (ionization and de-ionization) that you want to acheive. Some of the Nixies datasheets for multiplexing specify a 100uS pulse as the shortest ionization pulse width in these datasheets and roughly 200-400uS for de-ionization pulse width this was also due to how the transistors were able to switch these voltages and not only due to the Nixies. Modern transistors are able to switch these currents and voltages faster than the older types so you could possibly have shorter pulses which acheives the same effect. The most common way of looking at the pulses and currents/voltages involved, by these books and datasheets, is by using the average voltage/current and not the RMS values since the pulses are square pulses and not sinusoidal waves or triangular waves. Here's a nice sheet showing RMS, Mean and their relationships: http://www.yokogawa.com/gmi/pdf/Bulletin/Bull-DMMglossary-E.pdf . There are quite a few examples in the book I mentioned above on how the Nixies were designed to be driven in those days. This is not the only book showing how this is suppsed to be done, but all that I have found have been written in German, there are possibly some english books to which show these details, probably from Philips or Valvo as they published a lot of design examples. I have been quite happy with the German books as they are easier to find and I guess were also printed in larger quantities and not so collectable as the English ones, which I guess is the reason why they are harder to find. /Martin On 16 mar, 09:54, Cobra007 wrote: > That makes sense indeed. > > What would the reason be to choose for a higher voltage rather than a > lower anode resistor? You can achieve a higher tube current by either > raising the voltage or lowering the resistor, so what is the advantage > of raising the voltage? Is it because ionization will be quicker or > doesn't have that anything to do with it? > > Michel > > On Mar 16, 7:13 pm, Dekatron42 wrote: > > > > > Many manufacturers write that you will have to contact them for the > > special curves you need when you are going to multiplex their Nixies > > since they do not usually print that information in the databooks. > > > These sheets show you that the Nixie will have an increased turn-on > > voltage corresponding to the increased current when run in switched > > mode. This is the same as when a neon voltage stabilizer tube is used, > > the voltage increases somewhat when the current increases, you can > > check the OB2 voltage regulator tube for instance. > > > The curves for most Nixies when used in multiplexed mode are not > > linear so if you can't find those curves you'll have to make the > > measurements yourself and take into account the spread between > > different Nixies to draw the curve. Some of these special curves have > > a voltage span of approximately 10-30V for a certain current through > > the Nixie, so there is an upper and a lower limit for the turn-on > > voltage corresponding to the current used. > > > This book:http://www.oldtimeradio.de/BU7908.php"Electronica 171 - > > Elektronische Anzeigebauelemente" by Winfired Müller contains a few of > > these curves for the ZM-series of Nixies. > > > /Martin > > > On 16 mar, 00:55, Cobra007 wrote: > > > > Yes, I think I mentioned "slightly" increase rather than a mayor > > > increase. > > > > I have measure this on another nixie tube and came to the following > > > voltages: > > > 0.5mA : 120V > > > 1.0mA : 125V > > > 1.5mA: 130V > > > 2.0mA: 133V > > > 3.0mA: 140V > > > 4.5mA: 150V > > > > His tube current will increase from 2mA to about 7.5mA, so according > > > to the above measurements, the increase in tube voltage will be > > > playing a role. > > > > Michel > > > > On Mar 16, 10:06 am, Charles MacDonald wrote: > > > > > On 12-03-15 05:46 AM, Cobra007 wrote: > > > > > > So it looks like your resistor is correct. The only thing is that the > > > > > voltage across the tube will slightly increase due to the higher > > > > > current, so it's not 100% correct but pretty much. > > > > > Since we are talking a Neon device, the voltage across the tube will try > > > > to stay the same, with the current adjusting if needed. That is why > > > > Neon bulbs were used as Voltage reference devices in days of Old. > > > > > -- > > > > Charles MacDonald Stittsville Ontario > > > > cm...@zeusprune.ca Just Beyond the > > > > Fringe
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
That makes sense indeed. What would the reason be to choose for a higher voltage rather than a lower anode resistor? You can achieve a higher tube current by either raising the voltage or lowering the resistor, so what is the advantage of raising the voltage? Is it because ionization will be quicker or doesn't have that anything to do with it? Michel On Mar 16, 7:13 pm, Dekatron42 wrote: > Many manufacturers write that you will have to contact them for the > special curves you need when you are going to multiplex their Nixies > since they do not usually print that information in the databooks. > > These sheets show you that the Nixie will have an increased turn-on > voltage corresponding to the increased current when run in switched > mode. This is the same as when a neon voltage stabilizer tube is used, > the voltage increases somewhat when the current increases, you can > check the OB2 voltage regulator tube for instance. > > The curves for most Nixies when used in multiplexed mode are not > linear so if you can't find those curves you'll have to make the > measurements yourself and take into account the spread between > different Nixies to draw the curve. Some of these special curves have > a voltage span of approximately 10-30V for a certain current through > the Nixie, so there is an upper and a lower limit for the turn-on > voltage corresponding to the current used. > > This book:http://www.oldtimeradio.de/BU7908.php"Electronica 171 - > Elektronische Anzeigebauelemente" by Winfired Müller contains a few of > these curves for the ZM-series of Nixies. > > /Martin > > On 16 mar, 00:55, Cobra007 wrote: > > > > > > > > > Yes, I think I mentioned "slightly" increase rather than a mayor > > increase. > > > I have measure this on another nixie tube and came to the following > > voltages: > > 0.5mA : 120V > > 1.0mA : 125V > > 1.5mA: 130V > > 2.0mA: 133V > > 3.0mA: 140V > > 4.5mA: 150V > > > His tube current will increase from 2mA to about 7.5mA, so according > > to the above measurements, the increase in tube voltage will be > > playing a role. > > > Michel > > > On Mar 16, 10:06 am, Charles MacDonald wrote: > > > > On 12-03-15 05:46 AM, Cobra007 wrote: > > > > > So it looks like your resistor is correct. The only thing is that the > > > > voltage across the tube will slightly increase due to the higher > > > > current, so it's not 100% correct but pretty much. > > > > Since we are talking a Neon device, the voltage across the tube will try > > > to stay the same, with the current adjusting if needed. That is why > > > Neon bulbs were used as Voltage reference devices in days of Old. > > > > -- > > > Charles MacDonald Stittsville Ontario > > > cm...@zeusprune.ca Just Beyond the > > > Fringehttp://users.trytel.com/~cmacd/tubes.html > > > No Microsoft Products were used in sending this e-mail. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Many manufacturers write that you will have to contact them for the special curves you need when you are going to multiplex their Nixies since they do not usually print that information in the databooks. These sheets show you that the Nixie will have an increased turn-on voltage corresponding to the increased current when run in switched mode. This is the same as when a neon voltage stabilizer tube is used, the voltage increases somewhat when the current increases, you can check the OB2 voltage regulator tube for instance. The curves for most Nixies when used in multiplexed mode are not linear so if you can't find those curves you'll have to make the measurements yourself and take into account the spread between different Nixies to draw the curve. Some of these special curves have a voltage span of approximately 10-30V for a certain current through the Nixie, so there is an upper and a lower limit for the turn-on voltage corresponding to the current used. This book: http://www.oldtimeradio.de/BU7908.php "Electronica 171 - Elektronische Anzeigebauelemente" by Winfired Müller contains a few of these curves for the ZM-series of Nixies. /Martin On 16 mar, 00:55, Cobra007 wrote: > Yes, I think I mentioned "slightly" increase rather than a mayor > increase. > > I have measure this on another nixie tube and came to the following > voltages: > 0.5mA : 120V > 1.0mA : 125V > 1.5mA: 130V > 2.0mA: 133V > 3.0mA: 140V > 4.5mA: 150V > > His tube current will increase from 2mA to about 7.5mA, so according > to the above measurements, the increase in tube voltage will be > playing a role. > > Michel > > On Mar 16, 10:06 am, Charles MacDonald wrote: > > > > > On 12-03-15 05:46 AM, Cobra007 wrote: > > > > So it looks like your resistor is correct. The only thing is that the > > > voltage across the tube will slightly increase due to the higher > > > current, so it's not 100% correct but pretty much. > > > Since we are talking a Neon device, the voltage across the tube will try > > to stay the same, with the current adjusting if needed. That is why > > Neon bulbs were used as Voltage reference devices in days of Old. > > > -- > > Charles MacDonald Stittsville Ontario > > cm...@zeusprune.ca Just Beyond the > > Fringehttp://users.trytel.com/~cmacd/tubes.html > > No Microsoft Products were used in sending this e-mail. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Yes, I think I mentioned "slightly" increase rather than a mayor increase. I have measure this on another nixie tube and came to the following voltages: 0.5mA : 120V 1.0mA : 125V 1.5mA: 130V 2.0mA: 133V 3.0mA: 140V 4.5mA: 150V His tube current will increase from 2mA to about 7.5mA, so according to the above measurements, the increase in tube voltage will be playing a role. Michel On Mar 16, 10:06 am, Charles MacDonald wrote: > On 12-03-15 05:46 AM, Cobra007 wrote: > > > So it looks like your resistor is correct. The only thing is that the > > voltage across the tube will slightly increase due to the higher > > current, so it's not 100% correct but pretty much. > > Since we are talking a Neon device, the voltage across the tube will try > to stay the same, with the current adjusting if needed. That is why > Neon bulbs were used as Voltage reference devices in days of Old. > > -- > Charles MacDonald Stittsville Ontario > cm...@zeusprune.ca Just Beyond the > Fringehttp://users.trytel.com/~cmacd/tubes.html > No Microsoft Products were used in sending this e-mail. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
On 12-03-15 05:46 AM, Cobra007 wrote: So it looks like your resistor is correct. The only thing is that the voltage across the tube will slightly increase due to the higher current, so it's not 100% correct but pretty much. Since we are talking a Neon device, the voltage across the tube will try to stay the same, with the current adjusting if needed. That is why Neon bulbs were used as Voltage reference devices in days of Old. -- Charles MacDonald Stittsville Ontario cm...@zeusprune.ca Just Beyond the Fringe http://users.trytel.com/~cmacd/tubes.html No Microsoft Products were used in sending this e-mail. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Interestingly, I just realize, if you work this further out you come to the following formula: Rmux = Rdc * (T1/T) Rdc is the anode resistor in direct drive (55V / 2mA = 27.5k) Rmux is the anode resistor in a multiplexed system = 27.5k * 0.267 = 7.3k :-) Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
It's a bit of a mind game this problem. I was wondering why use rms values instead of average values. In the end, the result should be the same I guess. I had another go at this problem through another approach. The rms power is defined as the heat dissipated by a resistor due to a voltage V(t) that is the same as if the resistor was powered by a DC voltage. So I thought why not take that as a beginning. In direct drive you want 2mA through each tube. The tube voltage (as measured) is about 145V and power supply voltage is 200V. This leaves 55V across the anode resistor. For direct drive, the dissipated heat in the anode resistor would be 55V * 2mA = 110mW = Pdc. When you go to multiplexed mode, all powers will stay the same because you want to achieve the same tube brightness. Therefore, the loss in the anode resistor will also stay the same. The rms voltage across the resistor is 55V * sqrt(T1/T) with T1/T = 0.267, Vrms will be 28.42V Then we can calculate the resistor as R = (Vrms ^ 2)/Pdc which is (28.42 ^ 2)/0.11 = (surprisingly) 7.3k So it looks like your resistor is correct. The only thing is that the voltage across the tube will slightly increase due to the higher current, so it's not 100% correct but pretty much. This calculation seems ok to me unless I missed something. Michel On Mar 14, 8:10 pm, Imbanon wrote: > IN-14 strike at 170V, but when multiplexed this should be a bit > higher. That's why it's set to 200 volts. It then drops to 140V > according to the datasheet, but in reality, I measured 144. So if I > take 200-140 it's 60 volts across the anode resistor, giving the peak > of 8mA. > But to be honest, I am really confused with this. By my calculations, > with 26.7% duty cycle per tube, for current of 2mA, I should have a > peak of 3.864mA ( 2/sqrt(0.267) = 3.864). > So with my supply stable at 200V and anode resistors of 7.5K, I should > get the 8mA peak on one tube, or 16mA on two tubes, but I really > measure current of 6.4mA alltogether that goes from my supply. How is > this possible? Why should my supply give me 48mA when I need only > 6.5mA for two tubes at a time? By the way, I am using blanking period > of 200us, so maybe the current really settles by this time, so the > supply needs to give enough current for only 2 tubes. > Can someone clear this out to me? > > And about that spider web.. it isn't really as messy as it looks in > the video. It's just a matter of viewing angle. And everything is > organised by cable color. > > Thanks > > On Mar 14, 1:24 am, Cobra007 wrote: > > > > > > > > > Wow, I like that spider web you created there! > > > How exactly did you estimate that a 7.5k resistor would result in a > > 8mA tube current? Honestly, I do not know the nominal voltage of the > > tube but I don't think it will be less than 150V. In that case, you > > have a maximum of 50V across your resistor which would only be 6.7mA. > > If you measure 5.5mA, the voltage across the resistor would be 41.25V > > so in that case, your resistor should have been between 4.7k and 5.2k > > to come to 8mA. My best guess is 4.7k. Try one tube and see if the > > value is then closer to 8mA for that tube. Also check that your 200V > > stays stable and can supply the required 48mA. > > > Michel > > > On Mar 14, 10:56 am, Imbanon wrote: > > > > Got my hands on some older Tektronix oscilloscope and a Fluke 199c. I > > > did quite a lot of measurements, even with the current probe. I > > > learned a lot about the tubes and their behaviour, but didn't really > > > solve my problem. > > > I ended up calculating my anode resistors (around 7.5k), that should > > > give a peak of 8mA, but gives 5.5mA measured with a scope. You can see > > > the result in the video below. The quality isn't at it's finest, but > > > it's better than nothing! > > > Check it out and tell me what you think. > > > Also, the supply is set to 200V. It that too > > > much?http://youtu.be/p7QNEL8s4l4 > > > > Thanks everyone > > > > On Mar 6, 10:10 pm, "Frank Bemelman" > > > wrote: > > > > > AC DMM’s always excluded the DC component, if I am not mistaken. For a > > > > mainly > > > > troubleshooting tool (citation needed), that is not a bad choice. After > > > > all, > > > > many AC signals > > > > found in circuits have a DC offset. Assuming sinewaves makes the design > > > > of > > > > the meter > > > > easier (cheaper). > > > > > I would not expect a different behaviour from a DMM that is TRUE RMS. > > > >
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
ld be 41.25V so in that case, your resistor should have been between 4.7k and 5.2k to come to 8mA. My best guess is 4.7k. Try one tube and see if the value is then closer to 8mA for that tube. Also check that your 200V stays stable and can supply the required 48mA. Michel On Mar 14, 10:56 am, Imbanonwrote: Got my hands on some older Tektronix oscilloscope and a Fluke 199c. I did quite a lot of measurements, even with the current probe. I learned a lot about the tubes and their behaviour, but didn't really solve my problem. I ended up calculating my anode resistors (around 7.5k), that should give a peak of 8mA, but gives 5.5mA measured with a scope. You can see the result in the video below. The quality isn't at it's finest, but it's better than nothing! Check it out and tell me what you think. Also, the supply is set to 200V. It that too much?http://youtu.be/p7QNEL8s4l4 Thanks everyone On Mar 6, 10:10 pm, "Frank Bemelman" wrote: AC DMM s always excluded the DC component, if I am not mistaken. For a mainly troubleshooting tool (citation needed), that is not a bad choice. After all, many AC signals found in circuits have a DC offset. Assuming sinewaves makes the design of the meter easier (cheaper). I would not expect a different behaviour from a DMM that is TRUE RMS. Nice to have that AC/DC switch though, on the Tek meters. But I m still a Fluke only guy ;-) Frank From: Nick Sent: Tuesday, March 06, 2012 4:03 PM To: neonixie-l@googlegroups.com Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current Yes, RMS has only one physical definition, but in the case of DMMs the actual implementation is obfuscated. "true" RMS in a DMM context is an RMS calculation that does not assume a sine wave - most cheaper DMMs do indeed assume a sine wave input. Then there are "true RMS" (and indeed "ordinary" RMS) DMMs that may or may not include any DC component, or at least in the Tek case, give you the choice. Old meters indeed did use to measure the heat produced in a resistor - the definition of the "RMS value" used was that of the DC voltage that would give the equivalent heating effect to the signal under inspection. Nick On Tuesday, March 6, 2012 2:16:45 PM UTC, GastonP wrote: Actually there is only a definition of RMS, not subject to "trueness" :) http://en.wikipedia.org/wiki/Root_mean_square AFAIK, the old instruments that gave a true-"true RMS" output measured the heat generated by the signal when applied to a resistor. That way the waveform shape did not affect the measurement, and they were able to measure with the DC component included, something fake-"True RMS" instruments can't do. Many of the existing instruments assume sinusoidal signals and thus are subject to gross errors. Gaston On Mar 5, 6:15 am, Nickwrote:>On Monday, March 5, 2012 8:46:42 AM UTC, Cobra007 wrote: Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't expect that to be honest as it undermines the definition of "true RMS" but a simple battery test shows 0V RMS :-). Its not a commonly known problem, even among professional EEs. One of my DMMs, a Tektronix DMM916, has the option to include/exclude any DC component as required. I've had "forthright" discussions with some over what theoretically constitutes true-RMS vs. what they expect/want in actuality. Nick -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visithttps://groups.google.com/d/msg/neonixie-l/-/cOKZXWW5GXwJ. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group athttp://groups.google.com/group/neonixie-l?hl=en-GB.- Hide quoted text - - Show quoted text - -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
> > >> tube but I don't think it will be less than 150V. In that case, you > > >> have a maximum of 50V across your resistor which would only be 6.7mA. > > >> If you measure 5.5mA, the voltage across the resistor would be 41.25V > > >> so in that case, your resistor should have been between 4.7k and 5.2k > > >> to come to 8mA. My best guess is 4.7k. Try one tube and see if the > > >> value is then closer to 8mA for that tube. Also check that your 200V > > >> stays stable and can supply the required 48mA. > > > >> Michel > > > >> On Mar 14, 10:56 am, Imbanon wrote: > > > >>> Got my hands on some older Tektronix oscilloscope and a Fluke 199c. I > > >>> did quite a lot of measurements, even with the current probe. I > > >>> learned a lot about the tubes and their behaviour, but didn't really > > >>> solve my problem. > > >>> I ended up calculating my anode resistors (around 7.5k), that should > > >>> give a peak of 8mA, but gives 5.5mA measured with a scope. You can see > > >>> the result in the video below. The quality isn't at it's finest, but > > >>> it's better than nothing! > > >>> Check it out and tell me what you think. > > >>> Also, the supply is set to 200V. It that too > > >>> much?http://youtu.be/p7QNEL8s4l4 > > >>> Thanks everyone > > >>> On Mar 6, 10:10 pm, "Frank Bemelman" > > >>> wrote: > > >>>> AC DMM s always excluded the DC component, if I am not mistaken. For a > > >>>> mainly > > >>>> troubleshooting tool (citation needed), that is not a bad choice. > > >>>> After all, > > >>>> many AC signals > > >>>> found in circuits have a DC offset. Assuming sinewaves makes the > > >>>> design of > > >>>> the meter > > >>>> easier (cheaper). > > >>>> I would not expect a different behaviour from a DMM that is TRUE RMS. > > >>>> Nice > > >>>> to have > > >>>> that AC/DC switch though, on the Tek meters. But I m still a Fluke > > >>>> only guy > > >>>> ;-) > > >>>> Frank > > >>>> From: Nick > > >>>> Sent: Tuesday, March 06, 2012 4:03 PM > > >>>> To: neonixie-l@googlegroups.com > > >>>> Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current > > >>>> Yes, RMS has only one physical definition, but in the case of DMMs the > > >>>> actual implementation is obfuscated. > > >>>> "true" RMS in a DMM context is an RMS calculation that does not assume > > >>>> a > > >>>> sine wave - most cheaper DMMs do indeed assume a sine wave input. > > >>>> Then there are "true RMS" (and indeed "ordinary" RMS) DMMs that may or > > >>>> may > > >>>> not include any DC component, or at least in the Tek case, give you the > > >>>> choice. > > >>>> Old meters indeed did use to measure the heat produced in a resistor - > > >>>> the > > >>>> definition of the "RMS value" used was that of the DC voltage that > > >>>> would > > >>>> give the equivalent heating effect to the signal under inspection. > > >>>> Nick > > >>>> On Tuesday, March 6, 2012 2:16:45 PM UTC, GastonP wrote: Actually > > >>>> there is > > >>>> only a definition of RMS, not subject to > > >>>> "trueness" :) > > >>>>http://en.wikipedia.org/wiki/Root_mean_square > > >>>> AFAIK, the old instruments that gave a true-"true RMS" output measured > > >>>> the heat generated by the signal when applied to a resistor. That way > > >>>> the waveform shape did not affect the measurement, and they were able > > >>>> to measure with the DC component included, something fake-"True RMS" > > >>>> instruments can't do. > > >>>> Many of the existing instruments assume sinusoidal signals and thus > > >>>> are subject to gross errors. > > >>>> Gaston > > >>>> On Mar 5, 6:15 am, Nick wrote:> On Monday, March > > >>>> 5, 2012 8:46:42 AM UTC, Cobra007 wrote: > > >>>>>> Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't > > >>>>>> expect that to be honest as it undermines the definition of "true > > >>>>>> RMS" > > >>>>>> but a simple battery test shows 0V RMS :-). > > >>>>> Its not a commonly known problem, even among professional EEs. One of > > >>>>> my > > >>>>> DMMs, a Tektronix DMM916, has the option to include/exclude any DC > > >>>>> component as required. I've had "forthright" discussions with some > > >>>>> over > > >>>>> what theoretically constitutes true-RMS vs. what they expect/want in > > >>>>> actuality. > > >>>>> Nick > > >>>> -- > > >>>> You received this message because you are subscribed to the Google > > >>>> Groups > > >>>> "neonixie-l" group. > > >>>> To view this discussion on the web, > > >>>> visithttps://groups.google.com/d/msg/neonixie-l/-/cOKZXWW5GXwJ. > > >>>> To post to this group, send an email to neonixie-l@googlegroups.com. > > >>>> To unsubscribe from this group, send email to > > >>>> neonixie-l+unsubscr...@googlegroups.com. > > >>>> For more options, visit this group > > >>>> athttp://groups.google.com/group/neonixie-l?hl=en-GB.- Hide quoted > > >>>> text - > > - Show quoted text - -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
. > >>> I ended up calculating my anode resistors (around 7.5k), that should > >>> give a peak of 8mA, but gives 5.5mA measured with a scope. You can see > >>> the result in the video below. The quality isn't at it's finest, but > >>> it's better than nothing! > >>> Check it out and tell me what you think. > >>> Also, the supply is set to 200V. It that too > >>> much?http://youtu.be/p7QNEL8s4l4 > >>> Thanks everyone > >>> On Mar 6, 10:10 pm, "Frank Bemelman" > >>> wrote: > >>>> AC DMM s always excluded the DC component, if I am not mistaken. For a > >>>> mainly > >>>> troubleshooting tool (citation needed), that is not a bad choice. After > >>>> all, > >>>> many AC signals > >>>> found in circuits have a DC offset. Assuming sinewaves makes the design > >>>> of > >>>> the meter > >>>> easier (cheaper). > >>>> I would not expect a different behaviour from a DMM that is TRUE RMS. > >>>> Nice > >>>> to have > >>>> that AC/DC switch though, on the Tek meters. But I m still a Fluke only > >>>> guy > >>>> ;-) > >>>> Frank > >>>> From: Nick > >>>> Sent: Tuesday, March 06, 2012 4:03 PM > >>>> To: neonixie-l@googlegroups.com > >>>> Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current > >>>> Yes, RMS has only one physical definition, but in the case of DMMs the > >>>> actual implementation is obfuscated. > >>>> "true" RMS in a DMM context is an RMS calculation that does not assume a > >>>> sine wave - most cheaper DMMs do indeed assume a sine wave input. > >>>> Then there are "true RMS" (and indeed "ordinary" RMS) DMMs that may or > >>>> may > >>>> not include any DC component, or at least in the Tek case, give you the > >>>> choice. > >>>> Old meters indeed did use to measure the heat produced in a resistor - > >>>> the > >>>> definition of the "RMS value" used was that of the DC voltage that would > >>>> give the equivalent heating effect to the signal under inspection. > >>>> Nick > >>>> On Tuesday, March 6, 2012 2:16:45 PM UTC, GastonP wrote: Actually there > >>>> is > >>>> only a definition of RMS, not subject to > >>>> "trueness" :) > >>>>http://en.wikipedia.org/wiki/Root_mean_square > >>>> AFAIK, the old instruments that gave a true-"true RMS" output measured > >>>> the heat generated by the signal when applied to a resistor. That way > >>>> the waveform shape did not affect the measurement, and they were able > >>>> to measure with the DC component included, something fake-"True RMS" > >>>> instruments can't do. > >>>> Many of the existing instruments assume sinusoidal signals and thus > >>>> are subject to gross errors. > >>>> Gaston > >>>> On Mar 5, 6:15 am, Nick wrote:> On Monday, March 5, > >>>> 2012 8:46:42 AM UTC, Cobra007 wrote: > >>>>>> Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't > >>>>>> expect that to be honest as it undermines the definition of "true RMS" > >>>>>> but a simple battery test shows 0V RMS :-). > >>>>> Its not a commonly known problem, even among professional EEs. One of my > >>>>> DMMs, a Tektronix DMM916, has the option to include/exclude any DC > >>>>> component as required. I've had "forthright" discussions with some over > >>>>> what theoretically constitutes true-RMS vs. what they expect/want in > >>>>> actuality. > >>>>> Nick > >>>> -- > >>>> You received this message because you are subscribed to the Google Groups > >>>> "neonixie-l" group. > >>>> To view this discussion on the web, > >>>> visithttps://groups.google.com/d/msg/neonixie-l/-/cOKZXWW5GXwJ. > >>>> To post to this group, send an email to neonixie-l@googlegroups.com. > >>>> To unsubscribe from this group, send email to > >>>> neonixie-l+unsubscr...@googlegroups.com. > >>>> For more options, visit this group > >>>> athttp://groups.google.com/group/neonixie-l?hl=en-GB. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
Why are you trying to achieve 8ma of current on IN-14's? Nominal supply current for that tube is 2.5ma, everything else is providing excessive current. Now, when multiplexing, lots of times we like to use excessive current to make the display brighter, but I wouldn't kill myself trying to achieve precisely 8ma - especially if it is a completely arbitrary number. In my multiplexed IN-14 designs, I use 180vdc supply and a 1x6 mux. I never overdrive the tubes, I'm pretty happy with the brightness as is... and the tubes will last a great deal longer. Do as Mike says, run the experiments and see for yourself. Also, be careful about taking Michel's advice... Lots of the things he says seem very strange to me. Do you have a schematic for your design? If this is a 1x6 multiplex, then you are only lighting one tube at a time. (or 2x3 is two tubes at at time) I don't follow how he is arriving at 48ma of supply current. :S -Adam W7QI On 3/14/2012 2:10 AM, Imbanon wrote: IN-14 strike at 170V, but when multiplexed this should be a bit higher. That's why it's set to 200 volts. It then drops to 140V according to the datasheet, but in reality, I measured 144. So if I take 200-140 it's 60 volts across the anode resistor, giving the peak of 8mA. But to be honest, I am really confused with this. By my calculations, with 26.7% duty cycle per tube, for current of 2mA, I should have a peak of 3.864mA ( 2/sqrt(0.267) = 3.864). So with my supply stable at 200V and anode resistors of 7.5K, I should get the 8mA peak on one tube, or 16mA on two tubes, but I really measure current of 6.4mA alltogether that goes from my supply. How is this possible? Why should my supply give me 48mA when I need only 6.5mA for two tubes at a time? By the way, I am using blanking period of 200us, so maybe the current really settles by this time, so the supply needs to give enough current for only 2 tubes. Can someone clear this out to me? And about that spider web.. it isn't really as messy as it looks in the video. It's just a matter of viewing angle. And everything is organised by cable color. Thanks On Mar 14, 1:24 am, Cobra007 wrote: Wow, I like that spider web you created there! How exactly did you estimate that a 7.5k resistor would result in a 8mA tube current? Honestly, I do not know the nominal voltage of the tube but I don't think it will be less than 150V. In that case, you have a maximum of 50V across your resistor which would only be 6.7mA. If you measure 5.5mA, the voltage across the resistor would be 41.25V so in that case, your resistor should have been between 4.7k and 5.2k to come to 8mA. My best guess is 4.7k. Try one tube and see if the value is then closer to 8mA for that tube. Also check that your 200V stays stable and can supply the required 48mA. Michel On Mar 14, 10:56 am, Imbanon wrote: Got my hands on some older Tektronix oscilloscope and a Fluke 199c. I did quite a lot of measurements, even with the current probe. I learned a lot about the tubes and their behaviour, but didn't really solve my problem. I ended up calculating my anode resistors (around 7.5k), that should give a peak of 8mA, but gives 5.5mA measured with a scope. You can see the result in the video below. The quality isn't at it's finest, but it's better than nothing! Check it out and tell me what you think. Also, the supply is set to 200V. It that too much?http://youtu.be/p7QNEL8s4l4 Thanks everyone On Mar 6, 10:10 pm, "Frank Bemelman" wrote: AC DMM’s always excluded the DC component, if I am not mistaken. For a mainly troubleshooting tool (citation needed), that is not a bad choice. After all, many AC signals found in circuits have a DC offset. Assuming sinewaves makes the design of the meter easier (cheaper). I would not expect a different behaviour from a DMM that is TRUE RMS. Nice to have that AC/DC switch though, on the Tek meters. But I’m still a Fluke only guy ;-) Frank From: Nick Sent: Tuesday, March 06, 2012 4:03 PM To: neonixie-l@googlegroups.com Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current Yes, RMS has only one physical definition, but in the case of DMMs the actual implementation is obfuscated. "true" RMS in a DMM context is an RMS calculation that does not assume a sine wave - most cheaper DMMs do indeed assume a sine wave input. Then there are "true RMS" (and indeed "ordinary" RMS) DMMs that may or may not include any DC component, or at least in the Tek case, give you the choice. Old meters indeed did use to measure the heat produced in a resistor - the definition of the "RMS value" used was that of the DC voltage that would give the equivalent heating effect to the signal under inspection. Nick On Tuesday, March 6, 2012 2:16:45 PM UTC, GastonP wrote: Actually there is only a definition of RMS, not subject to "trueness" :) http://en.wikipedia.org/wik
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
No, it is still not correct because the total power consumption doesn't add up. The 12mA DC current for the 200V supply is correct because you want 2mA for each tube. This means when multiplexing, a pair of tubes must have a maximum peak current of 12mA, not 6mA. That's where the problem is. 12mA @ 50V would be a 4k resistor. The easiest thing to do measure the DC current that the 200V power supply delivers, if that is 12mA you know that each tube has 2mA average current. Just use a (200V) parallel capacitor, then a series resistor (100R), then another (200V) parallel capacitor and then you can measure the voltage over the series resistor with a normal DMM, which should be 1.2V for 12mA. You probably need a resistor between 3k3 and 4k. Now it should be OK :-) Michel On Mar 14, 11:05 pm, Cobra007 wrote: > I can smell a misunderstanding here (from my side, that is). > > What are you trying to achieve? I just read your previous posts, it > seems like you're after 2mA average current per tube, so your power > supply should be able to deliver 12mA in total. > > I assume the anodes from the 2 tubes go through 1 resistor to the 200V > supply (2 anodes share 1 resistor). > > The peak current for 2 tubes should be 6mA * (33.3 / 26.7) = 7.5mA > > With 60V across the resistor, you would then need 8k resistors. > > However, it is probably a bit less, maybe more like 6.8k as the > voltage is probably less than 60V. > > I really liked the spiderweb, that was not a joke, I think it looks > good. > > Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
I can smell a misunderstanding here (from my side, that is). What are you trying to achieve? I just read your previous posts, it seems like you're after 2mA average current per tube, so your power supply should be able to deliver 12mA in total. I assume the anodes from the 2 tubes go through 1 resistor to the 200V supply (2 anodes share 1 resistor). The peak current for 2 tubes should be 6mA * (33.3 / 26.7) = 7.5mA With 60V across the resistor, you would then need 8k resistors. However, it is probably a bit less, maybe more like 6.8k as the voltage is probably less than 60V. I really liked the spiderweb, that was not a joke, I think it looks good. Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
IN-14 strike at 170V, but when multiplexed this should be a bit higher. That's why it's set to 200 volts. It then drops to 140V according to the datasheet, but in reality, I measured 144. So if I take 200-140 it's 60 volts across the anode resistor, giving the peak of 8mA. But to be honest, I am really confused with this. By my calculations, with 26.7% duty cycle per tube, for current of 2mA, I should have a peak of 3.864mA ( 2/sqrt(0.267) = 3.864). So with my supply stable at 200V and anode resistors of 7.5K, I should get the 8mA peak on one tube, or 16mA on two tubes, but I really measure current of 6.4mA alltogether that goes from my supply. How is this possible? Why should my supply give me 48mA when I need only 6.5mA for two tubes at a time? By the way, I am using blanking period of 200us, so maybe the current really settles by this time, so the supply needs to give enough current for only 2 tubes. Can someone clear this out to me? And about that spider web.. it isn't really as messy as it looks in the video. It's just a matter of viewing angle. And everything is organised by cable color. Thanks On Mar 14, 1:24 am, Cobra007 wrote: > Wow, I like that spider web you created there! > > How exactly did you estimate that a 7.5k resistor would result in a > 8mA tube current? Honestly, I do not know the nominal voltage of the > tube but I don't think it will be less than 150V. In that case, you > have a maximum of 50V across your resistor which would only be 6.7mA. > If you measure 5.5mA, the voltage across the resistor would be 41.25V > so in that case, your resistor should have been between 4.7k and 5.2k > to come to 8mA. My best guess is 4.7k. Try one tube and see if the > value is then closer to 8mA for that tube. Also check that your 200V > stays stable and can supply the required 48mA. > > Michel > > On Mar 14, 10:56 am, Imbanon wrote: > > > > > > > > > Got my hands on some older Tektronix oscilloscope and a Fluke 199c. I > > did quite a lot of measurements, even with the current probe. I > > learned a lot about the tubes and their behaviour, but didn't really > > solve my problem. > > I ended up calculating my anode resistors (around 7.5k), that should > > give a peak of 8mA, but gives 5.5mA measured with a scope. You can see > > the result in the video below. The quality isn't at it's finest, but > > it's better than nothing! > > Check it out and tell me what you think. > > Also, the supply is set to 200V. It that too > > much?http://youtu.be/p7QNEL8s4l4 > > > Thanks everyone > > > On Mar 6, 10:10 pm, "Frank Bemelman" > > wrote: > > > > AC DMM’s always excluded the DC component, if I am not mistaken. For a > > > mainly > > > troubleshooting tool (citation needed), that is not a bad choice. After > > > all, > > > many AC signals > > > found in circuits have a DC offset. Assuming sinewaves makes the design of > > > the meter > > > easier (cheaper). > > > > I would not expect a different behaviour from a DMM that is TRUE RMS. Nice > > > to have > > > that AC/DC switch though, on the Tek meters. But I’m still a Fluke only > > > guy > > > ;-) > > > > Frank > > > > From: Nick > > > Sent: Tuesday, March 06, 2012 4:03 PM > > > To: neonixie-l@googlegroups.com > > > Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current > > > > Yes, RMS has only one physical definition, but in the case of DMMs the > > > actual implementation is obfuscated. > > > > "true" RMS in a DMM context is an RMS calculation that does not assume a > > > sine wave - most cheaper DMMs do indeed assume a sine wave input. > > > > Then there are "true RMS" (and indeed "ordinary" RMS) DMMs that may or may > > > not include any DC component, or at least in the Tek case, give you the > > > choice. > > > > Old meters indeed did use to measure the heat produced in a resistor - the > > > definition of the "RMS value" used was that of the DC voltage that would > > > give the equivalent heating effect to the signal under inspection. > > > > Nick > > > > On Tuesday, March 6, 2012 2:16:45 PM UTC, GastonP wrote: Actually there is > > > > only a definition of RMS, not subject to > > > "trueness" :) > > > >http://en.wikipedia.org/wiki/Root_mean_square > > > > AFAIK, the old instruments that gave a true-"true RMS" output measured > > > the heat generated by the signal when applied to a resistor. That way >
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Wow, I like that spider web you created there! How exactly did you estimate that a 7.5k resistor would result in a 8mA tube current? Honestly, I do not know the nominal voltage of the tube but I don't think it will be less than 150V. In that case, you have a maximum of 50V across your resistor which would only be 6.7mA. If you measure 5.5mA, the voltage across the resistor would be 41.25V so in that case, your resistor should have been between 4.7k and 5.2k to come to 8mA. My best guess is 4.7k. Try one tube and see if the value is then closer to 8mA for that tube. Also check that your 200V stays stable and can supply the required 48mA. Michel On Mar 14, 10:56 am, Imbanon wrote: > Got my hands on some older Tektronix oscilloscope and a Fluke 199c. I > did quite a lot of measurements, even with the current probe. I > learned a lot about the tubes and their behaviour, but didn't really > solve my problem. > I ended up calculating my anode resistors (around 7.5k), that should > give a peak of 8mA, but gives 5.5mA measured with a scope. You can see > the result in the video below. The quality isn't at it's finest, but > it's better than nothing! > Check it out and tell me what you think. > Also, the supply is set to 200V. It that too much?http://youtu.be/p7QNEL8s4l4 > > Thanks everyone > > On Mar 6, 10:10 pm, "Frank Bemelman" > wrote: > > > > > > > > > AC DMM’s always excluded the DC component, if I am not mistaken. For a > > mainly > > troubleshooting tool (citation needed), that is not a bad choice. After all, > > many AC signals > > found in circuits have a DC offset. Assuming sinewaves makes the design of > > the meter > > easier (cheaper). > > > I would not expect a different behaviour from a DMM that is TRUE RMS. Nice > > to have > > that AC/DC switch though, on the Tek meters. But I’m still a Fluke only guy > > ;-) > > > Frank > > > From: Nick > > Sent: Tuesday, March 06, 2012 4:03 PM > > To: neonixie-l@googlegroups.com > > Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current > > > Yes, RMS has only one physical definition, but in the case of DMMs the > > actual implementation is obfuscated. > > > "true" RMS in a DMM context is an RMS calculation that does not assume a > > sine wave - most cheaper DMMs do indeed assume a sine wave input. > > > Then there are "true RMS" (and indeed "ordinary" RMS) DMMs that may or may > > not include any DC component, or at least in the Tek case, give you the > > choice. > > > Old meters indeed did use to measure the heat produced in a resistor - the > > definition of the "RMS value" used was that of the DC voltage that would > > give the equivalent heating effect to the signal under inspection. > > > Nick > > > On Tuesday, March 6, 2012 2:16:45 PM UTC, GastonP wrote: Actually there is > > > only a definition of RMS, not subject to > > "trueness" :) > > >http://en.wikipedia.org/wiki/Root_mean_square > > > AFAIK, the old instruments that gave a true-"true RMS" output measured > > the heat generated by the signal when applied to a resistor. That way > > the waveform shape did not affect the measurement, and they were able > > to measure with the DC component included, something fake-"True RMS" > > instruments can't do. > > Many of the existing instruments assume sinusoidal signals and thus > > are subject to gross errors. > > > Gaston > > > On Mar 5, 6:15 am, Nick wrote:> On Monday, March 5, 2012 > > 8:46:42 AM UTC, Cobra007 wrote: > > > > > Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't > > > > expect that to be honest as it undermines the definition of "true RMS" > > > > but a simple battery test shows 0V RMS :-). > > > > Its not a commonly known problem, even among professional EEs. One of my > > > DMMs, a Tektronix DMM916, has the option to include/exclude any DC > > > component as required. I've had "forthright" discussions with some over > > > what theoretically constitutes true-RMS vs. what they expect/want in > > > actuality. > > > > Nick > > > -- > > You received this message because you are subscribed to the Google Groups > > "neonixie-l" group. > > To view this discussion on the web, > > visithttps://groups.google.com/d/msg/neonixie-l/-/cOKZXWW5GXwJ. > > To post to this group, send an email to neonixie-l@googlegroups.com. > > To unsubscribe from this group, send email to > > neonixie-l+unsubscr...@googlegroups.com. > > For more options, visit this group > > athttp://groups.google.com/group/neonixie-l?hl=en-GB. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Got my hands on some older Tektronix oscilloscope and a Fluke 199c. I did quite a lot of measurements, even with the current probe. I learned a lot about the tubes and their behaviour, but didn't really solve my problem. I ended up calculating my anode resistors (around 7.5k), that should give a peak of 8mA, but gives 5.5mA measured with a scope. You can see the result in the video below. The quality isn't at it's finest, but it's better than nothing! Check it out and tell me what you think. Also, the supply is set to 200V. It that too much? http://youtu.be/p7QNEL8s4l4 Thanks everyone On Mar 6, 10:10 pm, "Frank Bemelman" wrote: > AC DMM’s always excluded the DC component, if I am not mistaken. For a > mainly > troubleshooting tool (citation needed), that is not a bad choice. After all, > many AC signals > found in circuits have a DC offset. Assuming sinewaves makes the design of > the meter > easier (cheaper). > > I would not expect a different behaviour from a DMM that is TRUE RMS. Nice > to have > that AC/DC switch though, on the Tek meters. But I’m still a Fluke only guy > ;-) > > Frank > > From: Nick > Sent: Tuesday, March 06, 2012 4:03 PM > To: neonixie-l@googlegroups.com > Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current > > Yes, RMS has only one physical definition, but in the case of DMMs the > actual implementation is obfuscated. > > "true" RMS in a DMM context is an RMS calculation that does not assume a > sine wave - most cheaper DMMs do indeed assume a sine wave input. > > Then there are "true RMS" (and indeed "ordinary" RMS) DMMs that may or may > not include any DC component, or at least in the Tek case, give you the > choice. > > Old meters indeed did use to measure the heat produced in a resistor - the > definition of the "RMS value" used was that of the DC voltage that would > give the equivalent heating effect to the signal under inspection. > > Nick > > On Tuesday, March 6, 2012 2:16:45 PM UTC, GastonP wrote: Actually there is > > only a definition of RMS, not subject to > "trueness" :) > > http://en.wikipedia.org/wiki/Root_mean_square > > AFAIK, the old instruments that gave a true-"true RMS" output measured > the heat generated by the signal when applied to a resistor. That way > the waveform shape did not affect the measurement, and they were able > to measure with the DC component included, something fake-"True RMS" > instruments can't do. > Many of the existing instruments assume sinusoidal signals and thus > are subject to gross errors. > > Gaston > > On Mar 5, 6:15 am, Nick wrote:> On Monday, March 5, 2012 > 8:46:42 AM UTC, Cobra007 wrote: > > > > Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't > > > expect that to be honest as it undermines the definition of "true RMS" > > > but a simple battery test shows 0V RMS :-). > > > Its not a commonly known problem, even among professional EEs. One of my > > DMMs, a Tektronix DMM916, has the option to include/exclude any DC > > component as required. I've had "forthright" discussions with some over > > what theoretically constitutes true-RMS vs. what they expect/want in > > actuality. > > > Nick > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To view this discussion on the web, > visithttps://groups.google.com/d/msg/neonixie-l/-/cOKZXWW5GXwJ. > To post to this group, send an email to neonixie-l@googlegroups.com. > To unsubscribe from this group, send email to > neonixie-l+unsubscr...@googlegroups.com. > For more options, visit this group > athttp://groups.google.com/group/neonixie-l?hl=en-GB. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
AC DMM’s always excluded the DC component, if I am not mistaken. For a mainly troubleshooting tool (citation needed), that is not a bad choice. After all, many AC signals found in circuits have a DC offset. Assuming sinewaves makes the design of the meter easier (cheaper). I would not expect a different behaviour from a DMM that is TRUE RMS. Nice to have that AC/DC switch though, on the Tek meters. But I’m still a Fluke only guy ;-) Frank From: Nick Sent: Tuesday, March 06, 2012 4:03 PM To: neonixie-l@googlegroups.com Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current Yes, RMS has only one physical definition, but in the case of DMMs the actual implementation is obfuscated. "true" RMS in a DMM context is an RMS calculation that does not assume a sine wave - most cheaper DMMs do indeed assume a sine wave input. Then there are "true RMS" (and indeed "ordinary" RMS) DMMs that may or may not include any DC component, or at least in the Tek case, give you the choice. Old meters indeed did use to measure the heat produced in a resistor - the definition of the "RMS value" used was that of the DC voltage that would give the equivalent heating effect to the signal under inspection. Nick On Tuesday, March 6, 2012 2:16:45 PM UTC, GastonP wrote: Actually there is only a definition of RMS, not subject to "trueness" :) http://en.wikipedia.org/wiki/Root_mean_square AFAIK, the old instruments that gave a true-"true RMS" output measured the heat generated by the signal when applied to a resistor. That way the waveform shape did not affect the measurement, and they were able to measure with the DC component included, something fake-"True RMS" instruments can't do. Many of the existing instruments assume sinusoidal signals and thus are subject to gross errors. Gaston On Mar 5, 6:15 am, Nick wrote: On Monday, March 5, 2012 8:46:42 AM UTC, Cobra007 wrote: > Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't > expect that to be honest as it undermines the definition of "true RMS" > but a simple battery test shows 0V RMS :-). Its not a commonly known problem, even among professional EEs. One of my DMMs, a Tektronix DMM916, has the option to include/exclude any DC component as required. I've had "forthright" discussions with some over what theoretically constitutes true-RMS vs. what they expect/want in actuality. Nick -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/cOKZXWW5GXwJ. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
Actually the signal was applied to a "thermocouple" which was "one arm" of a bridge circuit. An "identical" thermocouple, which was a "second arm" in the same bridge circuit, then had D.C. applied to it. A null was then achieved across the bridge, and the meter actually measured the D.C. being applied. A very simple and elegant solution to the measurement issue of both wave shape and frequency. RMS is the A.C. voltage, regardless of wave shape, that will produce the ""same heating effect"" in a PURE resistance (think here of an incandescent lamp filament), as an EQUIVALENT amount of D.C. Applies to current as well. As an example a 100V RMS wave shape, will produce the same heating effect, in a pure resistance, as 100V D.C. RMS means "Root Mean Squared" of which there is a mathematical way of calculating it. It actually is a mathematical process. If you want more I'd suggest looking it up on Wikipedia, or other places on the net. Hope that this helps. Ira. On 3/6/2012 6:16 AM, GastonP wrote: Actually there is only a definition of RMS, not subject to "trueness" :) http://en.wikipedia.org/wiki/Root_mean_square AFAIK, the old instruments that gave a true-"true RMS" output measured the heat generated by the signal when applied to a resistor. That way the waveform shape did not affect the measurement, and they were able to measure with the DC component included, something fake-"True RMS" instruments can't do. Many of the existing instruments assume sinusoidal signals and thus are subject to gross errors. Gaston On Mar 5, 6:15 am, Nick wrote: On Monday, March 5, 2012 8:46:42 AM UTC, Cobra007 wrote: Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't expect that to be honest as it undermines the definition of "true RMS" but a simple battery test shows 0V RMS :-). Its not a commonly known problem, even among professional EEs. One of my DMMs, a Tektronix DMM916, has the option to include/exclude any DC component as required. I've had "forthright" discussions with some over what theoretically constitutes true-RMS vs. what they expect/want in actuality. Nick -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB. <>
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Yes, RMS has only one physical definition, but in the case of DMMs the actual implementation is obfuscated. "true" RMS in a DMM context is an RMS calculation that does not assume a sine wave - most cheaper DMMs do indeed assume a sine wave input. Then there are "true RMS" (and indeed "ordinary" RMS) DMMs that may or may not include any DC component, or at least in the Tek case, give you the choice. Old meters indeed did use to measure the heat produced in a resistor - the definition of the "RMS value" used was that of the DC voltage that would give the equivalent heating effect to the signal under inspection. Nick On Tuesday, March 6, 2012 2:16:45 PM UTC, GastonP wrote: > > Actually there is only a definition of RMS, not subject to > "trueness" :) > > http://en.wikipedia.org/wiki/Root_mean_square > > AFAIK, the old instruments that gave a true-"true RMS" output measured > the heat generated by the signal when applied to a resistor. That way > the waveform shape did not affect the measurement, and they were able > to measure with the DC component included, something fake-"True RMS" > instruments can't do. > Many of the existing instruments assume sinusoidal signals and thus > are subject to gross errors. > > Gaston > > On Mar 5, 6:15 am, Nick wrote: > > On Monday, March 5, 2012 8:46:42 AM UTC, Cobra007 wrote: > > > > > Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't > > > expect that to be honest as it undermines the definition of "true RMS" > > > but a simple battery test shows 0V RMS :-). > > > > Its not a commonly known problem, even among professional EEs. One of my > > DMMs, a Tektronix DMM916, has the option to include/exclude any DC > > component as required. I've had "forthright" discussions with some over > > what theoretically constitutes true-RMS vs. what they expect/want in > > actuality. > > > > Nick -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/cOKZXWW5GXwJ. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Actually there is only a definition of RMS, not subject to "trueness" :) http://en.wikipedia.org/wiki/Root_mean_square AFAIK, the old instruments that gave a true-"true RMS" output measured the heat generated by the signal when applied to a resistor. That way the waveform shape did not affect the measurement, and they were able to measure with the DC component included, something fake-"True RMS" instruments can't do. Many of the existing instruments assume sinusoidal signals and thus are subject to gross errors. Gaston On Mar 5, 6:15 am, Nick wrote: > On Monday, March 5, 2012 8:46:42 AM UTC, Cobra007 wrote: > > > Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't > > expect that to be honest as it undermines the definition of "true RMS" > > but a simple battery test shows 0V RMS :-). > > Its not a commonly known problem, even among professional EEs. One of my > DMMs, a Tektronix DMM916, has the option to include/exclude any DC > component as required. I've had "forthright" discussions with some over > what theoretically constitutes true-RMS vs. what they expect/want in > actuality. > > Nick -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
On Monday, March 5, 2012 8:46:42 AM UTC, Cobra007 wrote: > > Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't > expect that to be honest as it undermines the definition of "true RMS" > but a simple battery test shows 0V RMS :-). Its not a commonly known problem, even among professional EEs. One of my DMMs, a Tektronix DMM916, has the option to include/exclude any DC component as required. I've had "forthright" discussions with some over what theoretically constitutes true-RMS vs. what they expect/want in actuality. Nick -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/OsFsfd0TANQJ. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't expect that to be honest as it undermines the definition of "true RMS" but a simple battery test shows 0V RMS :-). Michel On Mar 5, 6:08 pm, Nick wrote: > Digital MMs sample and require a periodic waveform to give accurate results > - even so-called "true RMS" DMMs do this. The whole business of what > constitutes a "true RMS" reading is beyond the scope of this note - e.g. > how is any super-imposed DC level incorporated in the calculation - most > so-called true-RMS DMMs are AC coupled for the purposes of RMS > calculations, i.e. they ignore any underlying DC offset. > > Anyway, as the pulses are essentially square waves, the average current > (M:S ratio x peak) is a good first approximation to the RMS value. > > As the tubes are multiplexed, the current waveform will confuse any DMM - I > suspect even good Flukes and Tektronix ones will have the same problem. > > What you need is an analogue MM, like an old AVO or something with a needle > - the analogue movement smooths and averages the pulses - set it on a volts > range and measure the drop over the anode resistor - then measure the anode > resistor accurately using your DMM, and calculate the average current that > way (if the analogue meter you are using isn't a valve or FET-input type, > don't forget to compensate for the input resistance in parallel with the > anode resistor - it'll be something like 20,000 ohms/volt). Otherwise you > will need a 'scope to measure the voltage pulses and do the calculations > from those. > > Lot to be said for analogue MMs... > > Nick > > > > > > > > On Sunday, March 4, 2012 10:26:23 PM UTC, Imbanon wrote: > > > Hi all! > > > I have a question about multiplexed nixies (2x3 - 2 turned on at a > > time). > > First of all.. I cannot get a 2mA (or at least I think so) on my > > IN-14s. It lead me to completely remove the anode resistor! Can a > > nixie tube be harmed if it does not have an anode resistor? Without > > any resistors, I can get up to 1.8mA measured with my multimeter in DC > > mode. > > > So I figured to try to calculate it. I think that the multimeter in DC > > mode shows average readings (that's true, right?). So with the formula > > that the average current equals Vpp*T1/T, in which T1=4ma, T=13.6 and > > Iavg=1.8mA, Vpp equals 6.12mA. > > Is that really possible? I would say that the current would be much > > higher. My 555 supply is capable to deliver at least 15mA at 200V > > (tested). > > So with Vpp I calculated that by the RMS formula Irms=Vpp*sqrt(T1/T), > > RMS current is 3.32mA, which is impossible by my judgement of > > brightness. > > > I will hopefully get my hands on a scope this week to check out the > > real peak current. But is there anything I can do before, or even if I > > get a chance to use a scope? > > > Many thanks! -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
Digital MMs sample and require a periodic waveform to give accurate results - even so-called "true RMS" DMMs do this. The whole business of what constitutes a "true RMS" reading is beyond the scope of this note - e.g. how is any super-imposed DC level incorporated in the calculation - most so-called true-RMS DMMs are AC coupled for the purposes of RMS calculations, i.e. they ignore any underlying DC offset. Anyway, as the pulses are essentially square waves, the average current (M:S ratio x peak) is a good first approximation to the RMS value. As the tubes are multiplexed, the current waveform will confuse any DMM - I suspect even good Flukes and Tektronix ones will have the same problem. What you need is an analogue MM, like an old AVO or something with a needle - the analogue movement smooths and averages the pulses - set it on a volts range and measure the drop over the anode resistor - then measure the anode resistor accurately using your DMM, and calculate the average current that way (if the analogue meter you are using isn't a valve or FET-input type, don't forget to compensate for the input resistance in parallel with the anode resistor - it'll be something like 20,000 ohms/volt). Otherwise you will need a 'scope to measure the voltage pulses and do the calculations from those. Lot to be said for analogue MMs... Nick On Sunday, March 4, 2012 10:26:23 PM UTC, Imbanon wrote: > > Hi all! > > I have a question about multiplexed nixies (2x3 - 2 turned on at a > time). > First of all.. I cannot get a 2mA (or at least I think so) on my > IN-14s. It lead me to completely remove the anode resistor! Can a > nixie tube be harmed if it does not have an anode resistor? Without > any resistors, I can get up to 1.8mA measured with my multimeter in DC > mode. > > So I figured to try to calculate it. I think that the multimeter in DC > mode shows average readings (that's true, right?). So with the formula > that the average current equals Vpp*T1/T, in which T1=4ma, T=13.6 and > Iavg=1.8mA, Vpp equals 6.12mA. > Is that really possible? I would say that the current would be much > higher. My 555 supply is capable to deliver at least 15mA at 200V > (tested). > So with Vpp I calculated that by the RMS formula Irms=Vpp*sqrt(T1/T), > RMS current is 3.32mA, which is impossible by my judgement of > brightness. > > I will hopefully get my hands on a scope this week to check out the > real peak current. But is there anything I can do before, or even if I > get a chance to use a scope? > > Many thanks! -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/TaNgBU7JeL8J. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
If you direct drive them @ 12mA and you want to have them the same brightness when multiplexed, you will need to increase the current to 36mA (as they are only on for 1/3 of the time). Which means 12mA for 2 tubes at all times, 6mA per tube @ 33% duty = 2mA average current per tube. Adam is right, you cannot measure that accurately with a DC multimeter. I even tried with a Fluke true RMS multimeter and that gives rubbish readings as well. Michel On Mar 5, 9:36 am, Imbanon wrote: > I direct drived all 6 of them, delivering 12mA without a problem. > Tested only up to 15mA. Didn't want to go further.. > > Thanks again > > On Mar 4, 11:29 pm, Adam Jacobs wrote: > > > > > > > > > Disable the multiplexing, so that only 2 nixies are lit (and those lit > > at 100% duty cycle). THEN measure the current draw. You will not be able > > to accurately measure the peak current draw of a multiplexed nixie with > > a multimeter. . and YES, you definitely need a current limiting resistor > > or you will break your nixies. > > > -Adam > > > On 3/4/2012 2:26 PM, Imbanon wrote: > > > > Hi all! > > > > I have a question about multiplexed nixies (2x3 - 2 turned on at a > > > time). > > > First of all.. I cannot get a 2mA (or at least I think so) on my > > > IN-14s. It lead me to completely remove the anode resistor! Can a > > > nixie tube be harmed if it does not have an anode resistor? Without > > > any resistors, I can get up to 1.8mA measured with my multimeter in DC > > > mode. > > > > So I figured to try to calculate it. I think that the multimeter in DC > > > mode shows average readings (that's true, right?). So with the formula > > > that the average current equals Vpp*T1/T, in which T1=4ma, T=13.6 and > > > Iavg=1.8mA, Vpp equals 6.12mA. > > > Is that really possible? I would say that the current would be much > > > higher. My 555 supply is capable to deliver at least 15mA at 200V > > > (tested). > > > So with Vpp I calculated that by the RMS formula Irms=Vpp*sqrt(T1/T), > > > RMS current is 3.32mA, which is impossible by my judgement of > > > brightness. > > > > I will hopefully get my hands on a scope this week to check out the > > > real peak current. But is there anything I can do before, or even if I > > > get a chance to use a scope? > > > > Many thanks! -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
[neonixie-l] Re: Calculating multiplexed nixie's RMS current
I direct drived all 6 of them, delivering 12mA without a problem. Tested only up to 15mA. Didn't want to go further.. Thanks again On Mar 4, 11:29 pm, Adam Jacobs wrote: > Disable the multiplexing, so that only 2 nixies are lit (and those lit > at 100% duty cycle). THEN measure the current draw. You will not be able > to accurately measure the peak current draw of a multiplexed nixie with > a multimeter. . and YES, you definitely need a current limiting resistor > or you will break your nixies. > > -Adam > > On 3/4/2012 2:26 PM, Imbanon wrote: > > > > > > > > > Hi all! > > > I have a question about multiplexed nixies (2x3 - 2 turned on at a > > time). > > First of all.. I cannot get a 2mA (or at least I think so) on my > > IN-14s. It lead me to completely remove the anode resistor! Can a > > nixie tube be harmed if it does not have an anode resistor? Without > > any resistors, I can get up to 1.8mA measured with my multimeter in DC > > mode. > > > So I figured to try to calculate it. I think that the multimeter in DC > > mode shows average readings (that's true, right?). So with the formula > > that the average current equals Vpp*T1/T, in which T1=4ma, T=13.6 and > > Iavg=1.8mA, Vpp equals 6.12mA. > > Is that really possible? I would say that the current would be much > > higher. My 555 supply is capable to deliver at least 15mA at 200V > > (tested). > > So with Vpp I calculated that by the RMS formula Irms=Vpp*sqrt(T1/T), > > RMS current is 3.32mA, which is impossible by my judgement of > > brightness. > > > I will hopefully get my hands on a scope this week to check out the > > real peak current. But is there anything I can do before, or even if I > > get a chance to use a scope? > > > Many thanks! -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
