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Are capacitor charging circuits necessary? Answered

So I was looking at some coilguns and all of them have a circuit to control the charging, is this really necessary or can you just apply the voltage you want and let them charge.


Unless you power supply will be damaged by the initial current spike, all you need is a switch to disconnect the supply, and connect the coil. Even then, a low value resistor is all that is necessary to limit the current.

The charging circuits are usually to provide a few hundred volts to the capacitor bank from a low voltage battery or power supply.

Remember, if you charge DOL, then there's a good chance you'll blow a fuse or throw a breaker without a current limit...

I'm planning on bringing the voltage up to around 300v-500v and I don't want a big light bulb on my thing, I want it to be hand held. And I guess this is what the guys I am talking about have, but how hard is it to make a device that uses rapid on and off to limit the power, instead of wasting power and heat on a resistor.

Just use a power resistor. You aren't wasting much at all, if you work it out.

If you're going for direct-on-line charging, just put a 20W mains bulb in series with the cap and supply.