Voltage analog measurement with high voltage spikes

Hi everyone,

I edited this thread with a more detailed explanation of my problem:

I attached a circuit block diagram. I use a mosfet trigger switch to power the motor (high power rating => high current) for 91ms.
After that it stops directly with active braking inside the mosfet switch module.

I like to control the trigger module, and monitor the battery with a arduino.
I already tried to power the arduino directly on the battery but I think that by switching the motor off it produces very high voltage spikes because the mosfet switches the motor off.

I think I have to reduce those voltage spikes on my arduino power supply in order to protect my arduino module.

I’ve read about TVS diodes but I now how to implement them.

Maybe a snubber circuit?



No meaningful advice can be given if we don't know the exact circuit and voltages.
Post a circuit diagram.
A zener diode is generally a poor protector, since it doesn't work as expected when the Arduino is off.
A voltage divider to ~1volt with a 100n cap from analogue-in to ground, and using 1.1volt Aref in code could protect better.