CDI circuit

Thread Starter

James Ashworth

Joined Apr 17, 2021
5
Hi I have built 2 CDIs one works and 1 does not. I belive it fault lies with the zener diode 4.7v, 0.5w that protects the SCR gate as it works for a few sparks, then works intermittantly, then not at all. Guessing it stops doing it's job as it gets warm. Circuit Diad attached. Any clues?
 

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Thread Starter

James Ashworth

Joined Apr 17, 2021
5
I presume the zener is to provide a stable and limited signal to the SCR gate, resistor #5 is to put a load in the Zener circuit when voltage in the the exciter coil reverses.
 
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