Re: Low Voltage Resonate Tuing Methodology

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-uswest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Nathan,
           Sorry to hear about your bad experiences.

On 9 Apr 01, at 23:04, Tesla list wrote:

> Original poster: "Nathan Morris by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <themfam-at-home-dot-com>
> 
> All,
> I have been ripped off on ebay and I am tired of trying to go it on my
> own for caps. I am in need of a reliable source for caps that are
> suitable for TC use. Any suggestions in this area would be greatly
> appreciated.  I have also been contemplating a low voltage resonate
> tuning method using a signal generator. Is it possible and safe to
> inject a one volt 60 HZ signal directly into the primary while
> simultaneously moving the primary tap and monitoring the secondary
> output from the torroid with a scope?  The scope could be setup to
> display one or two periods of the calculated resonate frequency.  The
> tap would then be adjusted until the desired waveform is displayed.  A
> HV probe could be made using low tolerance resistors to protect the
> scope.  I'm sure I'm missing something here, I just don't know what it
> is.

The coils need to be tuned independently (unless you indulge in some 
offset tuning I descibed in an earlier post). The coupled system 
exhibits two responses, neither of which is the resonant frequency of 
either circuit. Low voltage tuning with a sig gen works well. 
     A caution - do not connect the scope probe to the secondary coil 
but pick up the signal from it with a small piece of wire attached to 
the scope probe and position a few feet away. Reason: the probe 
capacitance will alter the secondary tune. Also, make sure the 
connection of the secondary wire to the toroid is *good*. I once 
tuned a coil to perfection, then wondered why it wouldn't run when 
powered. Turns out, the terminal was not making contact at low 
voltages but immediately connected with high voltages completely 
altering the tuning.
     The probe may be directly connected to the primary when using 
the sig gen as the primary capacitance is huge compared with the 
scope probe capacitance.

Regards,
malcolm