14 Oct
2008
14 Oct
'08
3:34 p.m.
Jim Battle wrote:
bfranchuk at jetnet.ab.ca wrote:
What? That answer is nonsense.
The answer wasn't stated so it cannot be nonsense.
Or maybe, like the cat in the box, it both is and isn't
until you look :-)
Voltage and energy are two very different things, as
you must know.
The correct answer can be found by using the equation
E=mc^2. How
massive is this 2.7kF capacitor? :-)
As long as the capacitor isn't moving or changing shape or
composition[*],
then you might find 0.5*C*V*V to be the energy.
C was given, I was looking for a possible V.
Maybe we're drifting too far off topic. For how long could
such a capacitor, fully charged, keep a ZX80 running, assuming
a 100% efficient inverter?
Antonio
[*] ISTR a problem stated in an old issue of an IEE magazine:
Take an oil filled jar used as a capacitor of capacitance C.
Charge it to voltage V. Disconnect the voltage source. Drain the
oil into an identical capacitor (initially uncharged). Describe
the final disposition of charges, voltages, energy, anything else
that takes your fancy.