Welcome to the group; I assume no responsibility if you get addicted to nixie tubes, and all sorts of vintage display devices.
Be very careful about how much current you pass thru a nixie; too much will cause premature wearout and too-little can result in cathode poisoning. Also, be aware that nixie tubes have non-linear characteristics, especially in the region where ionization occurs. Initially, the current in the nixie is zero as you increase the voltage to just below the point where ionization occurs. As the voltage is slightly increased you can see very faint glowing, and the current is usually below 100uA. When the voltage is bumped-up slightly, the voltage drop across the tube reduces and the current increases. This region is unstable and exhibits negative resistance. If you limit the current with a resistor, you will see a steady glow and the voltage across the tube will be significantly less than the ionization voltage. The graph below is data I collected for a b7971 tube. Visible glowing occurs above 135V; ionization started as high as 180V in some cases . Once the cathode has ionized, though, it has reasonably linear behavior: More voltage across the tube results in more current, hence higher brightness. Now, getting to your question, you definitely want an anode resistor to limit the current; without it your design will be unstable and the nixie current will be determined by the tube's raw characteristics, which vary from tube-to-tube, as well as over time. I suggest you learn first with a direct-drive design, then work on multiplexing. [image: ScreenHunter_15 Jan. 21 14.08.jpg] -- 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/513eb93d-3672-42c6-a6b9-ded554048f7c%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
