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PWM circuit to drive ignition coil

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Most Helpful Member
It would be easier and much cheaper to just build one yourself. All you need is a basic Timer IC like a 555 or something similar to drive a high voltage Mosfet or IGBT switching device.


New Member
Generally a PWM motor controller should work.

Consider the high clock frequency when pulsing an ignition coil, which might overheat.

Here is a cheap circuit using the CMOS-version (TLC555) of the NE555.

The PRF (pulse repetition frequency) is fixed at 1 to 1.5 cycles/min with selectable pulse widths of 16.5, 24 and 31ms.


Note: S1 is a double pole three position slide switch for circuit safety reasons. If a single pole switch is used and fails the timer output might constantly go high causing the ignition coil to overheat and "kaputt". Don't omit the fuse for that reason.


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