Diode identification?
"John E." wrote:
Terry Given sez:
So it is possible that the zener was used to get a suitable rate of
decay (although ramp down is more accurate) of coil current.
I'm told that the solenoid this circuit operates is for a vacuum valve that
must operate quickly and repeatedly. It was thought by the person who handed
me this pcb that the solenoid was operated with 2 voltage rails, switching
between opposite opening voltage and closing voltage. But according to
measurements by him (and the fact that there's only 1 FET), the purpose of
the zener here seems to make sense.
But how can a 4.7v zener and one diode drop serve similar purpose as a 47v
part?
Consider how it works !
Graham
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