Re: DC Tesla Coil

From: 	Antonio Carlos M. de Queiroz[SMTP:acmq-at-compuland-dot-com.br]
Sent: 	Saturday, January 03, 1998 3:47 PM
To: 	Tesla List
Subject: 	Re: DC Tesla Coil 

Tesla List wrote:

>     If my tank capacitor is charged with DC only, it seems to me that it
> would be much easier to get a solid resonance occuring in the tank circuit
> with a fixed spark gap (well quenched)...

With resonance frequencies in the range of 100 kHz, 60 Hz AC or DC is the
same thing. AC is just easier to obtain at moderately high voltages and
high power.
In a normal Tesla coil circuit, the spark gap works as a switch, that keeps
the primary circuit connected, without interruptions, for time enough for
the complete transfer of energy from the primary circuit to the secondary
circuit. This may take a good fraction of a milisecond, after several tens
of cycles of oscillation. After the complete transfer, the gap shall open,
leaving the energy in secondary circuit to be gradually dissipated in
RF corona, sparks, and other losses. With the gap open, the primary capacitor
is charged again from the low-frequency supply, and the cycle is repeated.
Antonio Carlos M. de Queiroz