This week we used the oscilloscope to measure the voltage of a couple of different locations on a PCB with an MCU controlling a motor via a PWM signal to a MOSFET. We started by measuring the voltage across a capacitor in a RC circuit and saw the characteristic voltage charge up.

We then measured the voltage across the motor. We could see the PWM signal that was controlling it, and we could also see the voltage spikes as the motor was switched off. This is why a flyback diode is necessary to protect more sensitive electronics.

Finally we probed the serial output of the microcontroller and could decode the data.