Re: Tuning a tesla coil without high voltage power

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

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

A VERY simple way to provide low-power excitation to a TC is to connect
the primary capacitor and inductor IN SERIES across the contacts of a
buzzer, preferably one running on DC.  Each time the contacts open the
voltage across the coil will rise, charging the capacitor.  When the
contacts close again the primary circuit will be completed just as when
a spark gap is used.  This is the same basic principle as used in the
"kicker coils", and was used in the early days of "wireless" both to run
a transmitter from DC power (quite high-powered buzzers!), and also as a
signal source when coupled with a suitable resonant circuit.  During WW1
all sides used similar setups for "trench radios".  I have an old
General Radio Model No. 174B signal generator which uses a high-pitched
buzzer this configuration, and it works surprisingly well.

Ed