Re: efficiency of spark gaps vs tubes

To: tesla-at-pupman-dot-com
Subject: Re: efficiency of spark gaps vs tubes
From: Tesla List <mod1-at-pupman-dot-com>
Date: Sun, 5 Oct 1997 16:59:43 -0600 (MDT)
Approved: mod1-at-poodle.pupman-dot-com



---------- Forwarded message ----------
Date: Mon, 6 Oct 1997 10:59:50 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: tesla-at-pupman-dot-com
Subject: Re: efficiency of spark gaps vs tubes

Jim,
       Correct me if I'm wrong, but....

> From: Jim Lux <jimlux-at-earthlink-dot-net>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: efficiency of spark gaps vs tubes
> 
> Geoff Schecht made a comment to the effect that tubes were more efficient
> than spark gaps.  I made the same comment to James Corum and he pointed out
> that really wasn't the case.  With a Class C tube amplifier, the best
> practical efficiency is around 65-70%, that is, the switch (i.e. the tube)
> is dissipating 30% of the DC input power.  In a spark gap, the switch is of
> very low resistance, and dissipates very little power, and with a low duty
> cycle to boot. For a short gap in air, the voltage drop is going to be
> around 50 volts, so on a 15 kW coil with the primary at 15 kV, you are only
> dissipating, at most, 50 Watts in the gap. This is 99+% efficiency.

I rather think that Igap seems to have disappeared from the equation?

Malcolm
<huge snip>