Variable Resistor Symbol | Rheostat Symbol & Types of Variable Resistors and Applications

What is a Variable resistor:

A Variable resistor is a type of resistor in which the electric flow of current can be controlled by adjusting the resistance value. This variable resistor works the same as a normal resistor at a fixed value and if the resistance value increases in the variable resistor the current through the circuit decreases and if the resistance value decreases the current flow through the variable resistor increases. It is also used as voltage-controlled across devices in a circuit. The variable resistor must operate by sliding the contact (wiper) onto the electromechanical transducer and usually on the resistive element.

Variable Resistor Symbol:

variable resistor symbol


Types of variable resistors:


The potentiometer is a type of resistor and is a three-terminal resistor with a rotating contact. It functions as a potential divider If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. The principle of a potentiometer is that the potential dropped across a segment of a wire of uniform cross-section carrying a constant current is directly proportional to its length.

Potentiometer symbol


A resistor is an electrical component that resists the flow of electric current. It is used to control the amount of current flowing in a circuit, as well as to adjust the voltage level in a circuit. Resistors are typically made from materials such as carbon or metal, and their resistance is measured in ohms. They are widely used in electronic circuits to perform a variety of functions, including voltage division, current limiting, and power dissipation. They come in various types and shapes, such as fixed resistors, variable resistors, wire-wound resistors, and surface-mount resistors. The most common type is the carbon composition resistor, which is a simple and inexpensive option.

Applications of Potentiometers:

Potentiometers are commonly used to control electrical devices

  1. Volume controls in Audio Circuits.
  2. Potentiometers can be used as position mechanism transducers.
  3. Potentiometers are used in Joysticks.
  4. Variable Resistors are measurements of the distance or angles, tuning of the circuits, and many more.
  5. Potentiometers are used as amplifier gain control.
  6. The potentiometer is used as a voltage divider in the electronic circuit.
  7. The potentiometer is used in medical equipment.
  8. The potentiometer is used in radio and television (TV) receivers for volume control.

Potentiometer Symbol:

potentiometer Symbol circuits99


A Rheostat is a type of resistor the most common way to vary the resistance in a circuit continuously is to use a rheostat. The adjustable resistor is used in applications that require the adjustment of current or the varying resistance in an electric circuit. Rheostats are much related to the potentiometers in terms of construction, but they are not used as a potential divider, instead, they are used as variable resistors. The resistive wire is wound around an insulating ceramic core and the wiper slides over the windings

Rheostat circuit

Rheostat Applications:

  1. Rheostats are used in dim lights to change the intensity of light.
  2. It is basically used to adjust the magnitude of current in a circuit by changing length.
  3. Rheostats are used as the power controlling devices, which were connected in series with the load.
  4. Used in high-efficiency switching electronics.
  5. which are used in circuits to perform tuning or calibration.

Rheostat Symbol:

Rheostat Symbol


Variable Resistor Applications:

Variable resistors are widely used in a variety of electronic applications, including:

  1. Volume controls in audio equipment: Variable resistors are used to adjust the volume of music or speech.
  2. Light dimmers: Variable resistors are used to control the brightness of lights in homes and buildings.
  3. Motor speed control: Variable resistors are used to adjust the speed of electric motors in appliances and machinery.
  4. Temperature control: Variable resistors are used to control the temperature in heating and cooling systems.
  5. Potentiometers: Variable resistors are also used as potentiometers, which are devices that measure the electrical potential (voltage) in a circuit.
  6. Sensors: Variable resistors are used as sensors for measuring position, pressure, and other variables.
  7. Power control: Variable resistors are also used in power control circuits to adjust the amount of power delivered to a load.
  8. Filtering: Variable resistors are also used in filtering circuits to adjust the cutoff frequency of a filter.


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