A Potentiometer, usually called a pot, is essentially a voltage divider circuit combined into one package. Depending on your requirements, you get large, bulky, high-power potentiometers for electrical circuits and also small, lightweight, low-power potentiometers for electronic circuits.
Single-turn Potentiometer
Used for large currents – electrical applications
Trimmer Potentiometer
Used for large currents – electrical applications
It is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or a rheostat.
It has 3 terminals, 2 fixed ends at the extremes and 1 variable end in the middle.
The extreme ends form the terminals of the resistor. So if the extreme ends are connected into a circuit, you will have a fixed resistance across these terminals. The variable end is where the position of the wiper plays an important role. As the knob on the resistor is moved, the wiper inside slides on the resistance plate and the resistances between the extreme ends and the variable end changes
Terminals of the Potentiometer
Inside the Potentiometer
It is also commonly known as pot or potmeter. The rotary type of pot is used in audio control and tuning of an amplifier and also to control the sensitivity of a sensor. Different materials are used to construct potentiometers, including carbon composition, cermet, wire-wound, conductive plastic or metal film.
Why use a potentiometer ?
Potentiometer is really necessary in many of the day to day application, some of them are
Sound control : The potentiometer is used to control audio devices like changing the volume, attenuating the frequency and other properties of an audio signal.
The potentiometer is used in audio power amplifiers where it is called as a logarithmic potentiometer, it is called so because the amplitude of the human ear is logarithmic. The potentiometer balances the sound accordingly to the change in resistance, suppose an audio device with a min and max value of 0-10 has to be changed to half of the max value, the value on the potentiometer will be pointing at exactly 5 to give the desired volume.
Television : The potentiometer was used to control picture brightness, contrast, and color response in a television, also it was used in TV for vertical hold.
Motion Control : Potentiometers can be used as position feedback devices in order to create “closed loop” control, such as in a servomechanism. This method of motion control used in the DC Motor is the simplest method of measuring the angle, speed and displacement.
Transducers : The potentiometers are widely used in displacement transducers as they are easy to construct and also gives a very large output signal.
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