Thanks for this helpful info! I just need to find out what tube voltage I should expect for these tubes. Sounds like you think 165, so I'll go with that. I can adjust later, as you say.
On Mon, May 6, 2019 at 1:36 AM gregebert <[email protected]> wrote: > 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 a topic in the > Google Groups "neonixie-l" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/neonixie-l/gIa9ngzJVKk/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/6359ee9c-1f60-4448-9d62-74b8e9624409%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/6359ee9c-1f60-4448-9d62-74b8e9624409%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- 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/CAM%3DKN7wC%3D%3DNxrJ9jeN5QNmNk4LD1x5C3mtyu6m4CrPKEeATKqg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
