# Re: Coupling Questions & coil measurements

```Hi Robert,

> Original Poster: "Robert Jones" <alwynj48-at-earthlink-dot-net>
>
> Hi all,
>
> I have been reading the postings on this subject and I now think I
> understand the significance of coupling and quench.
>
> I good analogy of the system is two identical pendulums attached to the
> centre of a horizontal line but separated by a small distance.  If one
> pendulum is set swinging across the line, the amplitude of the other starts
> at zero then gradually increases as the amplitude of the first pendulum
> decreases to zero. Then the opposite happens.  The  energy repeatedly
> oscillates from one pendulum to the other.  The equivalent of quench is
> presumable when the first pendulum stops moving it is clamped and hence the
> second pendulum is forced to continue to swing.  I believe I saw this effect
> demonstrated on a OU program on UK TV.

Very close. Quenching implies removing the driving pendulum
altogether rather than clamping it. The idea is to cut off all
paths which could otherwise dissipate energy.

> How is the quench arranged to occur at the right time.

With very great difficulty. Practice suggests that removing energy
rapidly from the secondary in an attached discharge is about the
only way without incurring serious losses in the primary. Timed
airblasts might be an effective means but I've not heard of anybody
doing this..

> I have tried to derive the Laplace transform equations but it is tricky.
> Does some one have a Mathcad file with them in.  I have a Mathcad file some
> where that determines the best coil configuration for a high power RF tuned
> circuit.  I should be able to use some of the equation to define the Q of a
> Tesla primary and secondary.

I'd be interested to see how the program determined Q stacks up
with measurement.

Regards,
Malcolm

```