What is a good way to discharge 1000+ volts?

I’m not an electrician but doesn’t amperage and/or wattage play a part in answering this?

It would, but there will be virtually no amps.

Hmmm. They told me to change a broken lightbulb with half a potato when I was a kid…

To earth i guess via an insulated cable of suitable tollerance, with a robust switch, but i don’t know for sure.

I meant I instead on ok and and not an

So you have a capacitor, I imagine, that’s charged up to 1,140 volts?

Normally you discharge this type of thing through a shunt resistor—that is, you have a switch to a resistor that lets you discharge the voltage relatively slowly.

Depending on your application, you can make this happen automatically, that is, use a high-ohm resistor (maybe 1MOhm—do your own math to check) across your capacitor. You want the rate of discharge to be SLOWER than the charge circuit, so it stays topped off. When you remove power from the charging circuit, the resistor will drain the kilovolt from the capacitor automatically. Put a volt meter on the cap the first time you do this, and you’ll get an idea of how long it takes to be safe.

It gets dangerous if combined with high amperage. So you really need to look at the wattage and energy involved. @grumpyfish‘s advice is perfect.

the only problem is that I have no idea where to get such a resistor, as I can’t order online. I also want a fast discharge.

@XOIIO If you are in the US, you can probably buy them at Radio Shack.

What exactly are you trying to do?

I’m
In Canada.

shhh it’s a secret project

OK… what’s the capacity of your capacitor? Might be something like 100uF or 6.3nF?

Thats the thing, the capacitors aren’t marked!

Oh =) Well, assuming a rather large 1F capacitor, you’ve got 1140 Columbs of charge in there.

The discharge current is = charge / time (in seconds).

So if we discharge your capacitor in one second, we get 1140 Amps. That’s roughly 100 times the power supplied to your house.

You can calculate how big of a resistor you need for a given amperage then by working backwards. At your peak voltage, you have 1140 volts, and V = IR, and I = Q/t.

So for a given charge (here, 1140C) and a given maximum I, we can solve it this way:

I = 20A (that’s a LOT of power, you need something like 12 gauge wire to carry it)
20A = Q/t
t = 57 seconds to discharge

1140 = 20*R

R = 57 Ohms (only because I used 1F so my Columbs and Voltage are equal)

HOWEVER W=V*A so we’re looking at 22.8kW of power disappated in 1 minute. That’s roughly the amount of energy in a lightning bolt.

Okay, let’s go for something smaller.

I know I can easily get my hands on a 1 Watt resistor, so maybe 1 = 1140*A, which means that amps equals about 1 milliamp to safely discharge.

Going back around, we’ve got 1/1140 = 1140 / t

t = 361 hours
1140 = 1/1140 * R
R = 22.8kOhm (or so)

Now, this is all assuming that your unlabled capacitors can (1) hold 1000V without a problem (most will internally break down and/or explode well before that), (2) are rated to 1F (which is a BIG capacitor), and (3) have no internal resistance.

I would recommend wearing goggles, a welding jacket, and gloves while handling any of this.

Also, note that most LARGE capacitors have high internal resistances to keep things like this from happening. Flash bulb caps tend not to have as much internal resistance, but also have much smaller storage capacities.

Above all, be very careful, wear safety gear, respect the electricity, and make sure everything is turned off and powered down before you walk away.

(I actually recommend that you don’t mess around with voltages that big, but I don’t think you’d listen to me)

I measured tge capacitor I have (the same as tge ones ill get) and it peaked at around 380 volts. and no… I’m not going to listen :)