Variable Resistor (potentiometer)
You've been using variable resistors for a long time without being ,aware of them. The volume control on a radio or television set is a variable resistor, for example.
So are the tone controls on a stereo receiver. And we've already used the Control in this Kit in some earlier projects.
In this Project we'll get a good idea of just how the Control in your Kit works. As you make the wiring connections for this Project, notice the schemata symbol for a variable resistor. The arrow pointing at a resistor gives a good picture of what goes on as you turn on.
Only as much resistance as you want is used and is introduced in the circuit at the arrow. The rest of the resistance in the Control is left "unused" as far as the circuit is concerned. Rotate potentiometer. Notice how the Meter swings back and forth?
It swings smoothly back and forth as you turn the potentiometer. There's no sudden large jump in the Meter reading. This sort of action is called linear. That means if you were to make a graph of the Meter reading and Control position you'd find the graph had a nearly straight line on it (don't believe us? Try it!)