[Mr V]

A potentiometer is just a voltage divider. One end gets wired to power the other to ground and the middle is your signal that will vary between 0-5v. Attach it to the pivot point and the voltage will correspond to where it is in its travel. No it does not tell you the angle directly but you don't really need that info you want to be able to drive it to a certain position. So you command your motor to run until you get the desired voltage output and then stop.