All sorts! One piece of equipment I use a lot is called an Oscilloscope. It’s used for looking at electronic signals on a circuit board to check that they’re correct. Are you familiar with a voltmeter or multimeter from your science or tech lessons? These are a simple device that will tell you what the voltage is at a point in a circuit.
An oscilloscope is basically a really fancy voltmeter – it has a screen with a graph on it, and it plots how the voltage in the circuit changes as time goes by. They’re really good, and I can see the voltage level going up and down even if it’s happening millions and millions of times a second!