Re: In vs. Out
From: John H. Couture[SMTP:couturejh-at-worldnet.att-dot-net]
Sent: Monday, July 21, 1997 4:39 PM
To: Tesla List
Subject: Re: In vs. Out
At 06:00 PM 7/20/97 +0000, you wrote:
>From: richard hull[SMTP:rhull-at-richmond.infi-dot-net]
>Sent: Sunday, July 20, 1997 3:49 AM
>Subject: In vs. Out
>I have been quietly following the input vs. output rounds between John
>Couture, Malcolm Watts, and John Freau. It seems each has a valid point and
>the bottom line is which end of the coil you are looking at and what your
>usage is in the end.
>I am more in the John F. and Malcolm W. camp, but see and view things from
>John C. is structuring his argument to look at the coil from the engineering
>aspect. Being an engieer myself, I can see this argument has real merit.
>Johns approach is sound. It is just that few coilers are at a point where
>real output energy can be measured accurately. With the engineering brain I
>see spark and naturally am willing to assume more spark out = more energy
>out. This seems a classically and thermodynamically sound assumption.
----------------------------- Big snip
>Richard Hull, TCBOR
Richard & All -
Welcome to our discussions on how coilers should proceed for the testing of
As Richard mentioned there appears to be two camps or viewpoints, the
engineering and the artistic. By artistic I understand that means experience
and craftsmanship. Regardless of the viewpoint, it is important that the end
results bring about the learning of the truth of how Tesla coils operate.
If a coiler is only interested in sparks I would not wish to criticize this
desire. However, I would like to see these coilers take more interest in the
methods used to test TC's such as the inputs and outputs involved for the
Richard's videos are very popular and interesting but leave a lot to be
desired if others wish to duplicate his efforts. It would be beneficial if
more information was available that gave the data in tabular and graphaical
At present the goal is to come up with an agreement on the method of
determining the watts per foot of spark for a Tesla coil. Although watts is
used it is understood that it is watts per second or energy. Two of the
possibilities are the use of power (one shot) or energy (continuous spark)
to represent the input and output of the TC system. It should be noted that
calling it a one shot method is taking some liberties with the concept of
energy. The one shot method would look at only the longest spark length. The
continuous method would consider the continuous spark length.
The problem with the one shot method is that the true input wattage in the
TC system that produced the spark is indeterminate. The input wattage for
the continuous method is an average and more easily determined. Also, the
output consisting of the continuous spark length is an average and can be
more accurately found.
I agree that most old hands can instantly gauge the performance of a coil
but that is a subjective opinion and not an engineering approach. I think we
should forget about spark brightness, color, etc. because these are also
subjective opinions or too difficult to measure. I would recommend that the
continuous method (controlled spark) be adopted because it makes more sense
from an engineering standpoint. The details would have to be worked out later.
Note that efficiency does not enter into the above testing setup. The
above gives us watts per foot of spark and the efficiency of a Tesla coil
can not be determined from this information. Determining the efficiency of a
Tesla coil involves parameters that require additional information about the