The directly driven tube is just 2mA and that doesn't light the pins. If I swap the tubes then it stays with the multiplexed tube.
On Monday, 30 October 2023 at 14:58:31 UTC Greg P wrote: > How much current are you using in a directly driven tube? I’ve had the > same issue with the pins lighting up with as little as 1mA on the Z570M > tubes. > > > On Monday, October 30, 2023 at 10:31:57 AM UTC-4 Craig Garnett wrote: > >> Increasing the HT gave me 10mA and looks pretty good but is this an issue >> in the photo? >> It only occurs in the multiplexed tube. >> >> Thanks >> Craig >> >> On Friday, 27 October 2023 at 18:13:19 UTC+1 Craig Garnett wrote: >> >>> 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 [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/172a5a66-bb3b-4f08-85c5-c69868d4e87fn%40googlegroups.com.
