Ignition Coil Interrupter

Chris · 2010-03-25T23:27:34+00:00

When I was a kid, I used to play with ignition coils. I made Teslacoils and the like from them. Yes, I know, a nerd's nerd.I used a relay wired as a buzzer to excite the low voltage side of thecoils. I always wondered about designing a solid state interrupter.I would imagine that regular transistors would not work, as the backEMF on the primary when the current is broken can reach severalhundred volts AC.Would an SCR work better in this application. I don't need linearmode components, just switched mode.Regards,Chris Maness

Mar 25, 2010 23 Replies

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Chris 16 years ago

I would imagine this would be limited to rather low frequencies. Unless one a rather potent 300V inverter. A tesla coil powered by

120VAC would be easy. Would 1uF be a good value for the capacitor that is going to dump into the primary?

Chris

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John Larkin 16 years ago

Sure, but it's not worth the effort. The discharge time is so fast the difference in power dissipation in the resistor is usually negligable.

For some values of "normally."

John

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Jamie 16 years ago

if you gate the B+ and fire the thyristor when the gate is opened, it'll allow you to fully drive the discharge cap with out the thyristor loading the B+ line. The R will not be needed.

This normally employs a inductor and diode on the B+ line prior the thyristor.

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