Jon;
One of the tasks of the plugwire resistance is to act as damping on the
spark current oscillation. There is inductance and capacitance in the
circuit, so when it's hit with a fast rise or fall- time pulse, it acts like
a resonant tank circuit and the current rings until it is damped to a
steady- state value. The current acts like a wheel that has hit a bump--
without the damping of a shock absorber (damper), the wheen just "rings" by
bouncing up & down.
RFI is primarily generated by this oscillation-- acting just like a
broadband radio transmitter. "Resistor" spark plugs have a built- in
resistor that acts as damping on copper plug wires; I wouldn't advise trying
to use actual 1/4 watt resistors as they are usually rated at 200 to 500V.
Too much voltage drop across them will cause the resistor to break down.
Thanks for the invitation-- maybe I'll bring my Fender 50th Anniversary CD
over to your pit area.
Regards, Neil Tucson, AZ
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