Hi Nicholas,A pulse cap is a high energy discharge capacitor. So we use them in the tank circuit. It is the capacitor that is in series with the primary coil inductor. The transformer charges the capacitor while the gap is not conducting. When the gap conducts (rotary, trigger, or static gaps), the energy stored in the pulse cap dumps it's energy across the primary coil which is of low impedance. So a large current is formed and thus the electromagnet field that envelopes and couples the secondary coil. Because of the low impedance at discharge, the decay rate will be very quick and the cap needs to be rated for this pulse energy (di/dt) which is simply the change in current over time (as well as the repetitive rate at which the gap will conduct). Because coils operating in the low to mid kHz frequencies, some RF losses can affect heating of the dielectric. Therefore, decent repetitive high energy pulse caps typically use polypropylene, polystyrene, etc.. (low loss at frequency). Regardless of professional pulse caps or even homebrew MMC caps, the use of high energy pulse caps is highly recommended in the capacitor defined in the primary circuit.
Take care, Bart Nicholas Goble wrote:
Hi everyone. I've heard some talk about using pulse capacitors in a tesla coil and am a little confused as to how they are used, what they do, and how they do it. Sorry if that's a little vague, but can anyone give me an overview of what pulse capacitors are? Nicholas Goble _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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