Re: The PING Test

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
> 
> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
> 
> The Ping Test is the most fundamental of all Tesla coil tests. The TC
> operates using a dampened wave and the Ping test also uses a dampened wave
> unlike other tests. A robust pulse generator is needed for good results. I
> used a HP 214A which can produce  pulses of 100 volts into a 50 ohm load.
> These pulse generators are still available on the surplus market at
> resonable prices.

A simple oscillator made with a 555 timer, directly connected to the
coil, produces the same effect. Smaller of course, but the ringing
can easily be observed with an oscilloscope and an antenna.

> A crucial and difficult to determine TC parameter of the secondary coil is
> the Q factor of the coil. The Q factor can be used to estimate the secondary
> voltage of the TC. The equation is
>       Vs = Q x Vp   where Vs = secondary voltage
>       Vp = primary voltage

This is not correct. The maximum output voltage is given, in a
capacitive
discharge coil, by Vp*sqrt(C2/C1), where C2 is the combination of the
secondary coil self-capacitance and the capacitance of the terminal, and
C1 is the primary capacitor. A good fraction of this absolute maximum
can be easily reached with any decent Q, and infinite Q will not cause
the limit to be exceeded.

Antonio Carlos M. de Queiroz