scr causes transients

Alec_t

Joined Sep 17, 2013
11,525
The gate-to-cathode voltage is less than the gate-to-ground voltage, but still excessive in the sim. A gate-to-cathode capacitor (of even a few pF) should help to reduce that.
 
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Alec_t

Joined Sep 17, 2013
11,525
I was editing my post while you were posting. Even 0.01pF added gate-to-cathode is enough to pull the gate-cathode spike down to ~4V, so perhaps the spike is an artifact of the thyristor model.
 

Alec_t

Joined Sep 17, 2013
11,525
Ignore my above posts. My sim was mis-behaving. The gate-to-cathode voltage is the important one and peaks at ~ 3.6V. The diode Bordodynov added needs to have a reverse voltage rating greater than the peak capacitor voltage.
Edit: Interchanging the load resistor and thyristor would avoid the high gate voltage and is the usual arrangement in a CDI (cap discharge ignition) circuit.
 
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