I'm trying out the INS-1 indicator bulbs to replace the generic ones I use.
Datasheets are still in Russian, but google translate to the rescue!
|1 - The smaller cylinder||Anode|
|2 - The larger cylinder||Cathode|
See the dark dot in the pinout diagram? This matches a dot on the envelope of the indicator (image below). The dot is next to the anode pin. Another way of tell the anode from the cathode, as the table above suggests, is finding the pin that connects to the smaller cylinder.
|Firing Voltage, in V||65||90|
|Sustaining Voltage, in V||-||55|
Recommended current, providing sufficient brightness is 0.5mA.
Because the sustain voltage is about 55V, I'm using a 180V power supply and 0.5mA is required, about 270K current limiting resistor is used.