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Old 06-14-2008, 07:50 PM   #17 (permalink)
Xringer
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Quote:
Originally Posted by jamesqf View Post
No. If you look at instantaneous current flow, it will follow the same exponential decay curve as that voltage plot. You'd have a current flow of many amps for the first fraction of a second, declining to a fraction of an amp after several seconds. A battery would supply nearly constant current/voltage until it's depleted.
If by "many amps", you mean 1 amp, then you are right. The usec the switch
is closed, there will be 1 amp of current flow I=E/R (9 Watts of heat will come out of the resistor) and then over time, the voltage (and current) will drop off. And the heat will drop off slowly too.

To get a lot of amps flowing from the 10,000 farad capacitor, you could just
short it out with a heavy jumper wire. But, I would avoid being in the area,
since that 9 volts and some really high amperage just might vaporize any undersized jumper.

When I worked for NEC, we had 1.0 Farad 5V capacitors on some of the test gear. The caps were installed to preserve the data in the memory chips, in case of power failure.. They were used because the designer didn't want to use a Nicad battery. They worked very well. We never lost any data.
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