We've already talked about fixed resistors in an earlier unit. The value of fixed resistors remains constant and can not be changed. As you might have guessed the value of variable resistors can change. There a variety of types of variable resistors. Some change value based upon brightness, some based on temperature, and others based on force. In this unit we will be looking at potentiometers. These have a knob that you can turn to change their value.
Grab a couple potentiometers and a multi-meter. Determine the maximum value of the potentiometers and then measure the value as the knob is twisted.