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Re: Joules - Vrms or Vp (fwd)
---------- Forwarded message ----------
Date: Tue, 28 Jul 1998 01:23:08 -0400
From: Richard Hull <rhull-at-richmond.infi-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Joules - Vrms or Vp (fwd)
Tesla List wrote:
> ---------- Forwarded message ----------
> Date: Mon, 27 Jul 1998 18:30:28 -0500
> From: "Barton B. Anderson" <mopar-at-uswest-dot-net>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Joules - Vrms or Vp
>
> To List,
>
> Regarding the calculation for Joules..... J = 1/2 x C x
> V^2.
>
> Should V = Vp or should V = Vrms? Why? (if you know).
>
> All responses welcome,
>
> Bart
Capacitors are intrisically looked at as DC devices for the purpose of
using this equation and the voltage V is the actual voltage across the
capacitor at the time of discharge. (instantaneous voltage at T fire.
If AC is used then it could be anything between 0volts and Vpeak
(depending on when the capacitor is fired, as by a spark gap.
With a true sync gap, which is adjusted dead on, and firiing only at the
peaks of the input sine, it would be Vpeak. For 100% of all other gap
systems on AC .... it is a crap shoot with no way of computing the
energy in the system without a lot of careful instrumentation
techniques.
Richard Hull