# Changing PC keyboard LED indicators to neon indicators - need advice for circuit



## seanspotatobusiness (Dec 18, 2017)

I want to modify my keyboard for a retro cyberpunk look and replace my LED (scroll, caps and num lock) indicators with neon indicators. I can power a neon lamp from a low voltage using a laptop CCFL inverter but I was wondering if there's any way I could power three from one inverter. They cannot be connected in parallel because only the one with the lowest forward voltage (or whatever the correct terminology is) will light. They must be connected in series. Is there some way I could use transistors to move the neon lamps in and out of the circuit? When all lamps are off, the inverter would produce a potential of, like, a 1000 or more volts.


----------



## seanspotatobusiness (Dec 20, 2017)

I have designed this circuit which reroutes the output of the inverter to a resistor when the lamps are not lit to prevent the inverter producing a very high voltage when the lamps are not lit. I actually have two circuit designs but I don't know whether one is better than the other, other than the first using fewer components.


----------



## Lynx_Arc (Dec 20, 2017)

You may be able to wire a variable resistor inline with each lamp and tweak them to get them to light up the same in parallel.


----------



## snakebite (Dec 23, 2017)

reddish orange leds would be simpler.
but a simple resistor across your hv supply should keep it from running away.
since the neons need only a few ma ea feeding them from a high resistance like 100k solves the current hogging.43k might be fine.


----------

