I'm not able to reason-out how the last circuit acts as a regulator. Basically, the path from the 200V supply to Rload (output) is 2 diode-drops (base-emitter junction) in series with 100K of resistance. Assuming the nixie tube takes about 150V to ionize, a current of 0.5mA thru R1 causes a 50V drop.
Adding-up the voltage drops around the circuit, everything is accounted for: 200V supply = 0.5mA * 100K + Vbe +Vbe + Nixie_tube. Solving, the nixie tube will have around 148.6V, assuming Vbe of 0.7V. This is in the ballpark for nixie tubes. If you want 2mA, reduce R1 to around 25K. But I dont think it will act as a regulator when you change the supply; the current will also change. -- 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 post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/be8a0173-88ee-45cb-824c-65d07ec376d6%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
