Here is a schematic. Some notes about it: The filament (aka the cathode) should always have 1V across it. It has to be warm. When it is warm it has a resistance of about 30R. So the purpose of the resistor network there is that it cuts the 12V up into 3V, 1V and 8V (approximately). The filament is raised to 3V above 0 because we need to be able to vary the grid voltage from -3V to 0V with respect to the filament. So in this case, with the filament held at +3V, we can vary the grid voltage from 0V to +3V. When the grid is at 0V (-3V wrt to the filament), the lamp is fully off. When the grid is at +3V (0V wrt the filament), the lamp is fully on.
I made the grid voltage variable with the little resistor network off to the left, just to demonstrate this. I created the 50V anode potential with a 200K/100K resistor network across a 150V nixie power supply I happened to have. BTW, the tube will glow with an anode voltage all the way down to about 23V, so 3x9V batteries in series would be enough to get a glow out of it. In reality my 12V power supply was more like 10.5V so the resistor values I used were a little different. Also, the resistance from the anode to ground is not infinite, so the actual voltage of my nixie power supply was more like 220V, which I produced gradually to make sure I didn't go over 50V. Obviously an actual 50V power supply would be better! All of this is just to demonstrate the principles of the DM160, rather than to act as a recipe for how they should actually be controlled! I broke two lamps while experimenting, in different ways. In the first lamp I applied >1V to the filament and it burned out after a few seconds!. Second, a filament shorted to the grid so I couldn't control the grid voltage any more. The first problem was just me being dumb. I have no idea why the second problem occurred, so you have been warned! Fortunately these lamps are cheap, but I am concerned that there is no apparent reason for the second problem... -- 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/9112e349-b737-427f-aca8-d09f0997b465%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
