At 01:08 AM 12/10/99 -0600, Rodger wrote:
>Well, if I remember right (and I was never good at this) Joules are the same
>thing as watt-seconds which should be capacitance times the square of the
>voltage. So if you have 20,000 volts and 2000 pF of capacitance you have .8
>joules. That just doesn't seem right, does it?
Just as an FYI (and correction for above)...
(also note, this is for the steady state)
The energy stored in a capcitor, U(c) is:
U(c) = 1/2 x C x V^2
So, for above #'s U(c) = 0.4 Joules.
Also, if you ever care to calculate the energy stored in an inductor, U(l),
the equation is similar. An inductor is a current device (as you already
knew), so the equation has a current variable instead of voltage (as with
the cap.)
U(l) = 1/2 x L x I^2
Then you can also calculate the power consumed by the device (by using what
Rodger said above, which is true.)
Power (watts) = Joules / Seconds.
Enjoy!
-Anders.
