Amateur nixie-er here,
I have a handful of z5900m tubes that I just tested (their specs below).
The issue is, when I use a 20Kohm resistor on the anode (calculated by supply voltage - maintaining voltage / current), the anode current is much too high. Here are the results of my testing (resistor value - current):
20K - 9mA
30K - 6mA
47K - 3.7mA
56K - 3mA
68K - 2.5mA
82K - 2.1mA
91K - 1.9mA
When I finally got the current down to a "safe" level, the digits were much dimmer, but still lit just fine. The maintaining voltage was at 130v.
Any idea why the resistor has to be so much larger to drop the current to a recommended level?
Now that I think about it... this type of tube has two anode leads. I connected both to one 20K resistor. Do each need their own resistor?
--- Tube Specs ---
Min. Supply: 170v Min. Current: 1mA
Ignition: 150v Max Current: 2mA
Maintaining: 140v Max Pulse: 10mA
Extinguishing: 120v
I have a handful of z5900m tubes that I just tested (their specs below).
The issue is, when I use a 20Kohm resistor on the anode (calculated by supply voltage - maintaining voltage / current), the anode current is much too high. Here are the results of my testing (resistor value - current):
20K - 9mA
30K - 6mA
47K - 3.7mA
56K - 3mA
68K - 2.5mA
82K - 2.1mA
91K - 1.9mA
When I finally got the current down to a "safe" level, the digits were much dimmer, but still lit just fine. The maintaining voltage was at 130v.
Any idea why the resistor has to be so much larger to drop the current to a recommended level?
Now that I think about it... this type of tube has two anode leads. I connected both to one 20K resistor. Do each need their own resistor?
--- Tube Specs ---
Min. Supply: 170v Min. Current: 1mA
Ignition: 150v Max Current: 2mA
Maintaining: 140v Max Pulse: 10mA
Extinguishing: 120v