[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: purpose of a variac?



Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>


A second (separate) variac is used in series to adjust the current independent of the voltage (first variac).

Dr. Resonance

Hey coilers,

I've read several documents on the internet which claim that the power throughput of a TC can be adjusted using a variable transformer to power the supply transformer of the coil. I don't see how this could be done under regular circumstances. If the input voltage of the supply transformer is reduced, it's output voltage reduces as well. The voltage across the capacitors can never exceed the supply voltage (unless you use resonant charging which may destroy the secondary winding of your supply transformer). Since the spark gap in the tank circuit is best to be tuned just to fire at the absolute voltage peak for optimized performance it will never fire with reduced input voltage to the primary circuit.

Regards, Q.