The next plot shows the effect of
varying
C1,
between 0.01 F and 4 F, while
k
varies between 0.05 and
0.9. It can be observed that larger
C1
always result in larger output
voltage. With low
k, this
happens for just a small increase in
C1
before detuning reduces the effect, but after a certain value of
k, increasing
C1 increases the voltage
continuously, with it tending to a value proportional to
k for large
C1. The output voltage
is always greater than the normal with
C1 increased after k =
0.5, tending to twice the normal value for large
C1 and
k = 1. This is, however, of little
practical interest, since the system loses efficiency, with just a
fraction of the initial energy in
C1
being transferred to
C2.
Note the trenches again, with depths that vary periodically.
The two plots below illustrate the
effect of losses. In this case a resistance of 20 Ohms in parallel with
the output capacitance, corresponding to a quality factor
Q = 20 for the secondary circuit.
The variation of
L1
just produces more clearly defined peaks, practically at the same
places.
The variation of
C1
shows maxima skewed in the direction of larger
C1, and reduction in the
output voltage for large
C1.
(further increase in
C1
results again in the maximum output voltage proportional to the
coupling).
The trenches are smoother in these lossy cases.
For a regular Tesla coil, only the
range with low
k is of
interest, and there the effects of changing
L1 or
C1 are similar. But for
energy conversion devices operating with high coupling, the increase in
the output voltage caused by increasing
C1 may be of interest.
Thanks to Terry Fritz for the idea of making this kind of plot. These
were made with a program that I wrote, but the same thing can be done
with Terry's Scantesla program (see the archives of the
Tesla list) and a suitable plotting
program.