Protecting controller transistor outputs?

[Andrus Saar]

Hello

A question: in what way would it be most practical to protect the transistor output of a controller against overvoltage (for example when switching contactors or solenoid valves)?

Is it just a diode, a varistor, a TVS diode, etc?

And how to connect it to the output.

And what parameters would be sufficient for normal operation (voltage, current, etc).

And can you suggest some types.

Andrus

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