I was trying to help my friend fix an issue with his car not getting a signal to the coil (obviously this isn't the correct fix, but it has had the car running previously).
The circuit is driving the trigger of a car's coil pack, is driven by the distributor with around 12VDC.
R1 is 3.3k
R2 is also 3.3k
12v is enough for more than 30-50ma that the trigger pulls from datasheet
MOSFET failed with 1300 ohms gate to drain, 1100 gate to source.
Bench testing with 11.6v without the mosfet when opto is off, gate has 11.6v, on, 0.24v, seems to be working fine.
I'll spare you the details of when the mosfet is installed since it's failed.
He doesn't have an oscilloscope to test for voltages and claims the diode in the mosfet should be sufficient, what other options do we have to protect the mosfet and improve the circuit?