Quote:
Originally Posted by freddyzdead
My Greencaps have finally arrived. I found that out of the box they varied from 6 to 54 millivolts across them. Charging them one-by-one, starting at 3.3 amps, they took around 40 minutes to reach 2.5 volts. But 2 of them seemed to get to 2.5 volts while still drawing 1.4 amps. Not sure what's going on there. Or why they all had different charges on them initially. I'm leaving them overnight to see what they get to in the morning.
At one of my work places, I had a couple of 1uF 50,000 volt capacitors stored in a corner. Those things were lethal. They were used in a portable x-ray machine; They would be charged up and then discharged through the X-ray tube, producing a burst of X-rays. Fully discharged, and left to themselves, after a few days they would have several kV on them. Nasty bite. This would happen repeatedly, they would continually charge themselves up unless you fitted a shorting strap, which I certainly did after getting a few big surprises. I couldn't figure out where they were getting the electrons from. Must have been a bunch of loose ones lying around in the bottom.
|
I think it's better to think of batteries as a chemical reaction for creating (not storing) electrons, and capacitors are more of a high pressure storage of electrons directly (meaning you could potentially store a lightning strike or even static electricity in them). The closest analog for capacitors would be compressed air; the tank holds the charge, but must be filled by a compressor; the caps are like the air tank (without the compressor).
That said, there's still chemicals in them which could potentially generate a few stray electrons, not to mention the possibility of some electrons being jostled loose that were previously "stuck."
Hopefully that makes a bit of sense as to why you should always short-strap a cap.