On 11/26/2015 2:45 PM, embedded systems wrote:
> Instead a zenner, use a fast schottky diode connected with the anode=20
> at plus and the cathode on the load and drain. Zenner smoked because=20
> limits the overvoltage in the drain. Since there is no limiting=20
> current resistor it ends by burning.

I've been avoiding tying anything to the positive side of the load as=20
that would be outside of the circuit.

I'm going to try the resistor in series with the flyback diode, but not=20
sure how to calculate an appropriate-sized resistor for this. The theory=20
is that the current would instantaneously be the same when the MOSFET=20
switches off.  So even with a limiting resistor, there would be 4A=20
through the diode for a short time, right?


--=20
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