Re: FW: Re: Tesla Coil Efficiency Test

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Matt wrote:
> ... even the simple definition of output/Input is muddied in
> trying to achieve a consensus...

I don't see the difficulty with defining a measurable and
meaningful efficiency for a TC.  We have the input power as
drawn from the wall socket, and watts dissipated in streamers
as the output power.  What's wrong with

 efficiency = watts-to-streamer/watts-from-wall

in which the two powers are to be averaged over a large number
of bangs.

It would be convenient if this efficiency were factorised into

 efficiency = supply circuit efficiency * RF efficiency

since each can be measured separately by several different methods.

I would take the primary cap as the interface between the supply
circuit and the RF circuit, and define

 supply circuit efficiency = BPS * firing energy / watts-from-wall

 RF efficiency = watts-to-streamer/(BPS * firing energy)

John wrote:

> If you put the lamp in the secondary coil base lead will you not
> get a sample of only the current in the secondary coil? 

No, so long as the pri-sec coupling coefficient is high enough
for the energy transfer time to be short compared with the decay
time of the system.  Then we can treat the two coils as a single
entity with a single overall decay rate.  Therefore it doesn't
matter whether you couple the lamp 100% to the secondary, or 100%
to the primary, or some ad hoc mixture of the two as achieved by a
loop coupling.  
--
Paul Nicholson
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