A Potentiometer is a three-terminal variable resistor whose resistance is manually changed to control the flow of current. A potentiometer act as an adjustable voltage divider.
Potentiometers are also commonly called pot meters or pots. The most popular form of the potentiometer is the single-turn rotary potentiometer. This type of potentiometer is commonly used in audio volume controls (logarithmic taper) and many other applications.
Construction of Potentiometer
A potentiometer consists of three terminals, two of which are fixed and one of which is variable. The fixed two terminals of a potentiometer are connected across a resistive element called a track, and the third terminal is connected to a sliding wiper. A wiper moving along a resistive element changes the resistance of the potentiometer. As the wiper moves across the resistance track, the potentiometer resistance changed.
A potentiometer’s resistive element can be flat or angled. If the resistive element is flat, the wiper will move in a straight line. And if the resistive element is angled, the wiper moves in a rotary manner.
Working of Potentiometer
A potentiometer basically works on the principle of varying the resistance of a fixed resistor by moving a sliding/rotary contact or wiper. By changing the position of the wiper, the length of the resistive wire is changed. This change in the length of the wire is proportional to the change in the resistance and is also inversely proportional to the cross-sectional area of the wire.
Thus, the cross-sectional area of the wire and the current through the circuit remain constant, while the length of the resistance wire is variable. In a potentiometer, the input is applied between the fixed terminals and the output is recorded between the moving and fixed terminals.
Types of Potentiometer
There are two main types of potentiometer which are given below:
- Rotary Potentiometer
- Linear Potentiometer
Symbol of Potentiometer
Two symbols are used to represent potentiometer. One of them is more popular in America and the other one is considered as an international standard symbol for potentiometer. The American standard contains zigzag lines and the international standard contains a rectangular box with 3- terminals that are placed b/w two straight lines.
Applications of Potentiometer
- User controlled inputs
- Audio control
- Position or angle transducer
- Calibration and tuning
- Amplifiers
- Comparing EMFs