Home > categories > Consumer Electronics > Power Banks > How to charge a flash capacitor bank?
Question:

How to charge a flash capacitor bank?

I have a bank of 10 flash caps all rated at around 300v and about 160 mF apiece. How do I charge this?

Answer:

A DC power supply that can deliver about 290 volts (NOT over 300 volts) will do that. A series power resistor based on the current output of the supply will limit the peak charging current to a safe value. For example, a voltage doubler from the 120 VAC line will deliver 330 volts DC. If you can find a transformer with a 200 volt 1 amp secondary, that will produce about 280 VDC. A 100 ohm power resistor in series will limit the current to 3 amps. Peak power in the resistor would be 1000 watts. Resistors in this capacity are very expensive. I'd try 3 120 volt 200 watt light bulbs in series instead. Under that setup, charge time will be: time constant is 100x10x0.16 160 seconds, and several time constants will get you charged up. EDIT, I'm taking your word on the caps size, and the above calculations reflect that. But I think they are actually 160?F, not 160mF. The latter would be much too large to fit in a cameral. Capacitor manufacturers tend to use m when they mean ? for some reason lost in history. In that case, the series resistor need only be a 500 ohm 50 watt unit and the charge time will be a few seconds. .

Share to: