Re: Primary Q - A Brain Teaser

To: tesla-at-pupman-dot-com
Subject: Re: Primary Q - A Brain Teaser
From: Bert Hickman <bert.hickman-at-aquila-dot-com> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Tue, 17 Nov 1998 23:18:44 -0700
Approved: terryf-at-verinet-dot-com

Tesla List wrote:
> 
> Original Poster: Ed Phillips <evp-at-pacbell-dot-net>
> 
> "Come again? The voltage is plotted on a linear scale. The
> proportional voltage drop of total voltage on the first cycle is
> different to that on the next. In absolute terms, the voltage drop is
> definitely the same isn't it? That's what the scope showed anyway.
> 
> Malcolm"
> 
>         I haven't observed such behavior here, and the waveform of resonant
> decay has always looked exponential.  However, in Zennek's classic book
> on wireless telegraphy he talks about a "linear decay", which would be
> very close to what you have said.  If the arc resistance increases as
> the current drops, this could happen, I guess, but haven't noticed it
> here.  Of course, pretty reluctant to bring a scope near a working coil,
> so have just observed the secondary voltage as picked up with a probe
> several feet away.
> 
> Ed

Ed and Malcolm,

Morecroft in "Principles of Radio Communication" has an excellent
section describing linear decay when a spark gap is present in an LC
circuit. Excellent reference!

-- Bert --