> > I was planning to not multiplex my nixies, probably leaving all cathodes > connected directly to the HV line, and placing current liming resistors on > the cathodes. Was interested to see if I'd need to tweak any of the > individual resistor values uniform current/brightness. >
I only just reread what I wrote there, and realise I made a typo. I should have said I was going to connect all the anodes to the HV line... On Thursday, 7 March 2019 00:41:00 UTC+8, nixiebunny wrote: > > Another important fact about Nixie tube cathodes: turning on one cathode > by pulling it to zero volts causes it to steer all the available current > away from the other cathodes, causing them to be dark. This is why you only > need a 50V switch on each cathode. > The caveat is that if no cathodes are pulled to zero volts, then there > will be leakage current flowing through the tube that will destroy a 50V > transistor. This is why I used the TD62083 with its set of commutation > diodes, and connected the diode common anode pin to a 50V source in my > Nixie watch circuit. > It's also why I made the blanking mode that drops the anode voltage to > 100V, so that the cathodes all remain dark when blanked. > > Ah, well that comes back to the page I referenced in the opening: http://www.decodesystems.com/re-how-nixies-work.html. Maybe that was written in reference to having leaky cathode transistors? (With no voltage clamp, as in Fig. 4.) If I had say 300V+ transistors with sufficiently low leakage when off (< 10 uA) and a 170V power supply, would I be able to blank the tube safely by turning all transistors off? I'll have another look at power supplies. :) I was a little concerned about how to calculate the value of the loop compensation components. For my first attempt I figured I'd avoid the problem altogether by using one of Yan's power supplies, and focus on the segment driving circuitry. -- 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 post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/7026df09-ef22-408c-9e92-7daa3f5f2db6%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
