Thanks gregebert, I'll have a play with the HT voltage and report back. Craig
On Friday, 27 October 2023 at 16:33:12 UTC+1 gregebert wrote: > You can run nixie tubes at much higher voltages if you wish, it does no > harm as long as you increase the series resistor to keep the current within > spec. For example, my first nixie clock runs the B5092 tubes from a +340V > supply, and I used a larger resistor (75K I think) to get the optimal 2.2mA > current. Running at higher voltage gives you more design margin, but it > does waste more energy as heat. Generally my HV supplies run between +200 > and +220VDC; seems like every clock I make ends-up with a different power > supply design. So far, I've designed and built nixie clocks with B5092, > B6091, B7971, IN-18, and RZ568m tubes. > > I would bump your supply up to +200V, and adjust the resistor to get 8mA > of peak current (6:1 multiplexing). That will give plenty of voltage margin > as the tubes age. From the photo, 8mA looks nice. I recommend that you > view your tube as you vary the supply voltage to get currents between 5mA > and 12mA just so you can see the effect of current on brightness. You > should see that once the tube is lit "normally", increasing the current > doesn't make as much of a change visually. > > I dont run my tubes multiplexed for a variety of reasons. > > On Friday, October 27, 2023 at 1:38:06 AM UTC-7 Craig Garnett wrote: > >> Thanks gregebert >> >> My HT is a 12V module and is adjustable but the tube spec says 170V so I >> left it at that. >> Are you saying that it's safe to increase the HT to get maybe 10mA? >> >> Craig >> >> On Friday, 27 October 2023 at 05:06:34 UTC+1 gregebert wrote: >> >>> My concern is that over time as the tubes age your HV supply voltage >>> might be too low to ensure proper ionization. If it's not adjustable, you >>> can boost it with a series DC supply such as a wall-wart transformer or a >>> small isolated DCDC converter. Anything from +12 to +24 should work fine, >>> and the current is pretty low (12mA). >>> >>> Once you get the HV supply resolved, you will be able to get more >>> current thru the tubes. BUT......you may want to stay with 8mA. From the >>> photo, the tubes glow nicely. Tube wearout is an exponential function of >>> current, so staying at the lower currents is better for longer lifetime. At >>> some point, the current could be too low and you might see cathode >>> poisoning, but that's reversible. My gut feeling is that 8mA of pulsed >>> current should be fine. >>> >>> So, are you using rectified AC-mains as your DC supply ? No worries, >>> I've done that on several clocks and it can be done safely with proper >>> circuit design. >>> >>> On Thursday, October 26, 2023 at 7:28:18 AM UTC-7 Craig Garnett wrote: >>> >>>> The ongoing project of mine is coming on nicely but I need some >>>> reassurance with the way I'm driving the Z570s. >>>> >>>> There are two banks of 6 multiplexed tubes, from what I see from the >>>> datasheet these should run at 2ma static or up to 12ma as a 1 in 6 >>>> multiplex but that is using google to translate from the datasheet's >>>> German. >>>> >>>> The problem is that even with a 1K anode resistor I can't quite get 8mA >>>> from a 170V supply. >>>> The photo shows two tubes, the left is static at 2mA and the right is >>>> multiplexed at just under 8mA with a 1mS on time from a 170V supply and 1K >>>> anode resistor.. >>>> >>>> Is this ok or could I do it a better way? >>>> >>>> Thanks >>>> Craig >>>> >>> -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/3729e8f4-28c0-48f0-9fa7-0a27d604cd99n%40googlegroups.com.
