I have already looked at this question which looked like it would provide the answer:
But it didn't, so I also checked out these:
- Flyback Diodes and Relays
- Suppression diode for relays in ULN2803A
Which didn't either. So my question is:
When selecting a flyback diode for a relay, how can I determine whether the speed of the diode is adequate for the application?
I am not looking for diode suggestions, but rather:
- What specifications in the datasheet for a diode I would need to look at
- How I can calculate the required values from 1. , given whatever information is needed about the circuit that controls the relay coil, and the specs of the relay.
I presume it has to do with capacitances in the diode's datasheet among other things.
Edit: to clarify, I don't mind if the relay takes some time to turn off. What I am concerned with is ensuring protection of the controlling circuitry from the spike the coil generates when current to it from the controlling circuitry ceases.