Re: [neonixie-l] Re: Dekatrons with thyratrons
Thank you, Eric, Threeneurons. What I am taking away from this is: * Keep my thyratrons for the reason I bought them: spares for my Geiger counters. (I have two: because the original wasn't working, the Ebay vendor sent not the parts (missing GM tubes) I asked for, but a whole unit.) * Consider a build with thermionic tubes. Haven't used them before, but have been looking for an excuse. If I had lots of time and money, I'd love to convert a Verilog clock design back to discrete logic - with tubes! -- Matthew Smith Business: http://www.smiffytech.com Blog: http://www.smiffysplace.com Linkedin: http://www.linkedin.com/in/smiffy Flickr: http://www.flickr.com/photos/msmiffy Twitter: http://twitter.com/smiffy ABN 16 391 203 815 -- You received this message because you are subscribed to the Google Groups neonixie-l group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/524D3E6C.6020307%40smiffytech.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: Dekatrons with thyratrons
The Russians regularely used thyratrons, both cold cathode types and those with a heater to drive Dekatrons. What types do you have? /Martin On Wednesday, 2 October 2013 07:29:49 UTC+2, Smiffy wrote: Has anyone done/seen Dekatrons used in conjunction with thyratrons? I just happen to have some thyratrons which I bought as spares for a Russian Geiger counter I was repairing (fault was actually a gas voltage regulator tube.) They were actually being sold as decimal indicators for Nixie clocks, believe it or not! Didn't know if they might be used in some way between Dekatron stages, or anything like that. Sorry to bring H into an Ne forum ;-) -- You received this message because you are subscribed to the Google Groups neonixie-l group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/d549047e-da4c-49b4-8ad2-509d2bd4f217%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: Dekatrons with thyratrons
On Wednesday, October 2, 2013 4:01:58 PM UTC+9:30, Dekatron42 wrote: The Russians regularely used thyratrons, both cold cathode types and those with a heater to drive Dekatrons. What types do you have? Cold cathode. These: http://www.ebay.com/itm/250991574870 There are two in the Geiger probe, one connecting to each of the two GM tubes. Tubes outnumber semiconductors in these Geiger counters! M -- You received this message because you are subscribed to the Google Groups neonixie-l group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/f256bb76-dc21-4e27-882c-727640c3d6fa%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] Re: Dekatrons with thyratrons
On Wednesday, October 2, 2013 5:52:27 PM UTC+9:30, Tidak Ada wrote: They are useful, but consider the MTBF is 5000 h ! I wonder how that equates to actual firings, because I'd guess that it's energised time that counts. M -- You received this message because you are subscribed to the Google Groups neonixie-l group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a47baa35-59d7-42e9-b06d-479ec5c2ed93%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
RE: [neonixie-l] Re: Dekatrons with thyratrons
I don't know, but I have the figure from a datasheet. eric _ From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On Behalf Of Matthew Smith Sent: woensdag 2 oktober 2013 13:43 To: neonixie-l@googlegroups.com Subject: Re: [neonixie-l] Re: Dekatrons with thyratrons On Wednesday, October 2, 2013 5:52:27 PM UTC+9:30, Tidak Ada wrote: They are useful, but consider the MTBF is 5000 h ! I wonder how that equates to actual firings, because I'd guess that it's energised time that counts. M -- You received this message because you are subscribed to the Google Groups neonixie-l group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a47baa35-59d7-42e9-b06d-479ec5c 2ed93%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups neonixie-l group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/!%26!AAAYAPDddShx705MuX20yCpp0vvCgAAAEAAOEtyMg%2BZNklwDAUDubgsBAA%3D%3D%40zeelandnet.nl. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: Dekatrons with thyratrons
Depends if you just want to use one to step a dekatron, or need it between dekatrons, so the second one steps, per every revolution of the prior one. The interstage one could be a problem. That one would need to respond to the output of one dekatron, and then boost it to step the second. The largest output signal is usually ~35V. That's the voltage developed across a cathode resistor, when the count hits that cathode. The guides need to see a step from ~+40V, down to ~-40V, or a 80V change. And its important to bias the guides to ~+40V, because you need them to be higher than any main cathode, when not stepping. Doing this with thermionic tubes is not a problem. They don't need to be thyratrons either. A simple vacuum triode, such as a 12AU7, 6J6, or 6C4, will work. Just make sure their plate resistance is under ~25K. There are other small thyratons, with heaters, that will also work, like the 6D4, 5696, and 5663. Those have lower heater demands than the 2D21. But if you're going to have a heater, its easier to get regular vacuum triodes, than thyratrons. Plus you're design will be simpler, because you won't have to take measures to prevent the tubes from latching. Thyratrons will latch in DC circuits. Interstage stepping with cold cathode thyratrons, or what I call gas triggers, is a little more problematic. That is what that eBay listing is pointing at. They need a larger signal to trigger, and their output transition, is smaller, than a thermionic device. There are a few devices that were specifically made for this very function. The GTE175M comes to mind. I have the grand total of one, in my stash. There are a few tricks to improve the input. That is to bias it just below its tripping point, and AC coupling the pulse from the prior stage, to bring it over that threshold. Then the amplitude of that pulse need only be just larger than the difference between the hold off level, and the trigger point. For the GTE175M that's 10V. The difference between 173V, where its guaranteed not to trip, and 183V, where its sure to trigger. Set the bias to 170V, and make give it at least a 15V pulse. Can't do too much on the output side (cold cathode). Use the highest supply possible, for the particular tube. When ON, it will drop to its natural sustain level. That's pretty much fixed. Hope that the difference, between the supply and that sustain level, is at least 80V. Preferable more. If not, you're not going to be able to step a dekatron with this tube. With all thyratrons, thermionic, or cold cathode, a resistor, and capacitor is tied to plate, in a relax osc fashion. This creates a temporary power reserve. Their values are calculated such that when triggered, an output pulse of proper amplitude and duration, is generated. The cap should discharge to a voltage low enough to then extinguish the tube. No such provision is needed with a vacuum triode, or transistor. -- You received this message because you are subscribed to the Google Groups neonixie-l group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/0ca06fbe-97f7-4538-a652-62b83f423227%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
