Author Options:

HV capacitor bank charge indicator? Answered


I have a capacitor bank with three 330v capacitors (from disposable cameras, of course... those things are awesome) connected in parallel, but I'm planning to add more. I'd like to indicate when the device has been charged using an LED, but I'm pretty sure that most LEDs can't handle 330v. The disposable cameras often have indicator lights, so how do they do it, and how can I implement it with more capacitors?


I put an LED and resistor in parallel with another smaller ohm higher wattage resistor on the capacitor input.

As the capacitors charge the LED lights up, and when the capacitors are charged the LED goes out.

Alright, so something like this?

And any ideas about exact specs?


Actually I wire it like the first circuit.

As the capacitors charge the LED lights up.

Now this is for a 220 volt system you might want to use a 15 Ω 5 watt and 20 kΩ ¼ watt resistors for a 330 volt system.

Or you can modify a circuit like the second circuit.

Cap Charger.bmpBattery Monitor 1.gif

Ok, the best ones I can find locally are 120v. Would one of those work with three 330v capacitors?