Capacitors

Dave made a comment in my last blog entry about handing someone a charged up capacitor and I thought it deserved an entry in itself.

For those of you that are non-technical, a capacitor is basically an electronic component that stores an electrical charge. They're a bit like a battery, but if you short them out they'll discharge completely, sometimes with a bang and lots of sparks.

Back when I was working as a tech, we had some small tins that originally contained small plastic strips used as insulators to stop relay contacts contacting, handy for fault finding. These tins had a metal bottom, a metal lid and a cardboard middle. What we used to do was solder a two microfarad capacitor to the base and the lid. We'd then close it up, put a little notice on it telling people not to open it, charge the cap up to about 250 volts with a megger and leave it on someones desk.

Naturally, when you see something on your desk that says, do not open, you open it. It's human nature. People expect something to jump out of it when they open it. They don't expect to get zapped.

The funny thing is, sometimes someone would pick it up, get zapped and drop it, and the next person would pick it up and do the same thing, not realising that victim numer one had been zapped. Two for the price of one.

Maybe one day I'll tell you about the spiders and cockroaches I used to make from bits of wire, antistatic foam and heatshrink, or the time I hid a walkie talkie on someones desk and started transmitting from the other side of the workshop.

Ah, those were the days.