I made a small pulse circuit. More like a coil gun. I charge the cap bank (C1) up to about 1200V. I push a button (S1) and the charge in the cap bank is dumped via the SCR into the transformer and I get a nice single spark across the spark gap. This works fine, until it doesn't. Which is when the gate of the SCR gives out, I presume as shown in the scope view (channel 2, circled in purple) because it reaches like 250V. I don't know where this voltage comes from or how to stop it. It's suppose to only be 9V or so (note the value for R2 is probably wrong but irrelevant).
Does anyone know what is happening here or how to stop it? I've tried a BY448 diode across the + and - lines to suppress backemf but they just fry for whatever reason. Is an opt-islolator the only option to protect the gate?
Does anyone know what is happening here or how to stop it? I've tried a BY448 diode across the + and - lines to suppress backemf but they just fry for whatever reason. Is an opt-islolator the only option to protect the gate?