Re: Harmonics

Tesla List wrote:

> Usually the primary of a tesla coil is set to resonate at the SAME frequency
> that the secondary rings at.  this is akin to pushing a swing every time it
> rocks back.  However, there are some cases where the secondary is set to
> ring at a harmonic of pri freq  as you mentioned.  I am making such a device
> which actually has two secondaries inside a race-track style primary that
> resonate at different harmonics of the pri freq...  this interference wave
> between the output of the two secondaries will cause the coils to arc
> between eachother.

This setup would be with two identical coils wound in opposite
both tuned to the same frequency of the primary circuit.
A secondary tuned to an harmonic of the primary frequency would not
significant output, unless it has a very small top load, and is tuned to
a subharmonic of the primary frequency (ideally 1/3, 1/5, 1/7, ...). The
secondary would then operate as a transmission line, with several
and current nodes along its length. For a dramatic demonstration of this
effect, take a look at this demonstration setup, from an old instrument
This is a magnifier-type setup, composed of an induction coil as power
supply, an enclosed spark gap across its output, two primary capacitors 
(Leyden jars), a small primary-secondary Tesla transformer, and a long 
resonator coil with grounded wires at its sides. The four voltage 
oscillations along the long coil are visible by the corona that they 

Antonio Carlos M. de Queiroz