Yes, I typically use a PMOS device to regulate the current at the anode. You can also use a PNP, but the non-zero base-current needs to be accounted-for. I drive the gate with an isolated DCDC converter at roughly -12V; to make the current adjustable you can use a pot to drive the gate. Using a source-resistance of 1.6K ohms, the current is around 5mA. Let me know if you want me to post a schematic; I have additional protection for ESD and driver-failure.
And, yes, it costs more money to use a current-limiter rather than a simple series resistor, but I spend *SO* much $$ for nixie tubes, not to mention they are getting rarer, that it's OK for me. I'm sure it's overkill. I've also done current-regulation at the cathode side for segmented displays; you cant regulate the anode current because it varies based on the number of illuminated segments. One subtle note about the '1' numeral in a nixie tube: It's often constructed with 2 adjacent wires and located at the very rear of the tube. Though you would expect more brightness from a '1', it's obscured by all of the other cathodes in front so it doesn't appear to be much brighter compared to the other numerals. -- 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/0b7f8248-071d-46a7-88b9-fbd97c6410c1%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
