As a Rheostat:
The electric current flowing through an electrical circuit is determined by the amount of voltage applied and the total resistance of the electrical circuit (I=V/R).
If applied voltage is fixed and we reduce the circuit resistance, the flow of electric current through the circuit will be increased. On the other hand, if we increase the circuit resistance, the flow of electric current through the circuit will be decreased.
So by placing rheostat in the electrical circuit, we can control the flow of electric current in the circuit.
Potentiometer connection as a rheostat:
A potentiometer has three terminals, two outside terminal and one middle terminal.
- Connect any one of the outside terminals and middle terminal with your circuit and left one outside terminal unused.
- Best practice is to connect any outside terminal with one end of the circuit and other outside and middle terminal at the other end of the circuit.
As a voltage divider:
A voltage divider involves applying a voltage source across a series of two resistors.
We’ll call the resistor closest to the input voltage (V in) R1, and the resistor closest to ground R2. The voltage drop across R2 is called V out, that’s the divided voltage our circuit exists to make. That’s what’ll end up being a fraction of the input voltage.
We can use this equation to find the output voltage (V out):
Potentiometer connection as voltage divider:
If the outside pins connect to a voltage source (one to ground, the other to V in), the output (V out at the middle pin) will mimic a voltage divider. So if we connect potentiometer like this then we will get output as a voltage.