The exact anode voltage is not critical; it needs to be high enough to ensure the tube is reliably ionized over the life of the tube. 200 volts is a good value.
What matters the most is the *current*. If the current is too high, the tube's life will be reduced. If the current is too low, the brightness might be less than desired, and your tube may develop cathode poisoning, where portions of some cathodes dont fully illuminate. Generally, cathode poisoning is reversible so dont get overly concerned about it at the moment. The simplest method to limit anode current is to use an anode resistor. You can calculate the approximate value of the anode resistor from basic circuit theory: Anode_supply_voltage = (anode_current) * (anode_resistor) - Tube voltage. If your tube's voltage is 165V, and the anode supply is 200V, and the ideal anode current is 2.75mA, you would need about 12.7K for your anode resistor. After you setup a tube and your supply, measure the voltage across the anode resistor to calculate the current to make sure it's the right value. >From the formula, you will notice that variations the tube's voltage drop and the supply-voltage affect the current. But at higher supply voltages, the variations in these will have smaller impact on tube-current. My first nixie clock has a +340V anode supply, so I just use larger resistors and waste a bit more energy. Personally, I dont like anode resistors because the anode current will vary as the tube and power supply age, so I use a simple current limiter. I've posted about this a few times in the past so you can do a search for details. It's a matter of choice, and there are valid arguments a regulator is overkill. -- 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/6359ee9c-1f60-4448-9d62-74b8e9624409%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
