[ucc] [hwc] [committee] need some hardwares

[Leighton Haynes]

On Sun, Aug 13, 2006 at 12:44:35PM +0800, David Basden wrote:
> Is it actually that sane to do this with big caps? That charge is going
> to go somewhere, i'm assuming either as heat, or as an EMF if your
> screwdriver acts as an inductor.
> 
> Am I wrong, or is thing going to do one or more of the following;
> 
> 	- Dump a whole lot of heat into the cap, possibly doing evil
> 	  things to the electrolyte
> 	- Have the EMF around the screwdriver collapse, inducing current
> 	  back into the cap
> 	- Somehow dump the energy as heat into the screwdriver if there
> 	  are reasonable RC losses

I would expect a big enough capacitor discharge to result in vapourized
screwdriver. You could probably get nasty burns ;)

Of course, I doubt the caps have _that_ much energy in them in this
case.

> I'm wondering mainly about *really* huge caps, and how to deal with them
> safely. I'm thinking some sort of actual load across them rather than
> just shorting them maybe?

A large resistive load would be my best guess. And leave it on there. As 
someone else mentioned, capacitors can pick up enough charge from
'nowhere' to give you a nasty jolt. Lots and lots of suckers.. erm, car 
enthusiasts, have been done by those big mofo caps they shove in their 
boot to look cool :P

Leighton...

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