10 Differences Between Potentiometer And Rheostat (With Comparison Chart)

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What Is A Potentiometer?

Potentiometer

A potentiometer is a manually adjustable variable resistor with three terminals. Two terminals are connected to both ends of a resistive element, and the third terminal connects to a sliding contact referred to as a wiper, moving over the resistive element. The output voltage of the potentiometer is determined by the position of the wiper. Typically, a potentiometer functions as a variable voltage divider. The resistive element can be seen as two resistors in series where the wiper position determines the resistance ratio of the first resistor to the second.

Potentiometer is used to measure the electro motive force (emf) of a given cell, the internal resistance of a cell and comparing emf of different cells. It is also used as a variable resistor in many applications.

Resistors provide a fixed value of resistance that blocks or resists the flow of electrical current around a circuit, as well as producing a voltage drop in accordance with Ohm’s law. Resistors can be fabricated to have either a fixed resistive value by some external means.

There are two main types of manually adjustable potentiometers, that is, Rotary potentiometer in which the wiper moves along a circular path and Linear potentiometer in which the wiper moves along a linear path.

What You Need To Know About Potentiometer

  1. A potentiometer is a resistor with three terminals and a sliding contact with an adjustable voltage divider.
  2. A potentiometer is used as a measuring instrument or component in electronics.
  3. A potentiometer is made of resistive elements such as graphite, resistance wire, cermet and carbon particles.
  4. Potentiometer is mainly used in circuits to vary voltage or to give variable supply voltage.
  5. The main function of potentiometer is to vary voltage or voltage dividing.
  6. A potentiometer has low power and is used for audio devices, television control and as a transducer.
  7. The potentiometer is connected in parallel with the circuit.
  8. Potentiometer can be used as a rheostat.
  9. Rheostat cannot divide voltage.

Application of Potentiometer

There are several uses of a potentiometer. The three main uses of a potentiometer are:

  • Measuring the voltage across a branch of a circuit
  • Comparing the emf of a battery cell with a standard cell
  • Measuring the internal resistance of a battery cell

What Is A Rheostat?

Rheostat

A rheostat is a variable resistor which is used to control the flow of current by manually increasing or decreasing the resistance. It is able to vary the resistance in a circuit without interruption. Rheostats were often used as power control devices for example to control light intensity, speed of motors, heaters and ovens. However, because of their relatively low efficiency and with advancements in technology, they are no longer used for these functions anymore. As variable resistors, they are often used for tuning and calibration in circuits.

 Rheostat’s construction is equally similar to that of a potentiometer. A rheostat has two connections; the first connection is made to one end of the resistive element and the other connection to the wiper (sliding contact).

There are three main types of rheostat, that is:

  • Linear rheostat. In this type of rheostat, the wiper or slider moves in a linear path. Linear rheostats are normally used in laboratories for research and teaching.
  • Rotary rheostat. In this type of rheostat the resistive element is circular or angle and the wiper or slider moves in a rotary path.
  • Preset Rheostat. Generally used in a printed circuit board.

What You Need To Know About Rheostat

  1. A rheostat is a variable resistor with two terminals that forms connection with one end and the wiper or slider only.
  2. Rheostat is used to vary the resistance of a circuit.
  3. Rheostat is made of various materials such as fluids, metal ribbon and carbon disk.
  4. Rheostat is mainly used in circuits to vary current.
  5. The main function of rheostat is to control the flow of current.
  6. A rheostat is used in high power electronics and appliances such as mixers, fans, motors and motors of large industrial machines.
  7. Rheostat forms a serial connection with the circuit through which the flowing current is to be controlled.
  8. A rheostat cannot be used as a potentiometer.
  9. A potentiometer can divide voltage.

Applications Of Rheostat

  • Used to increase or decrease the volume of a radio and to increase or decrease the speed of an electric motor.
  • Used in devices or applications where high voltage is required.
  • Rheostats are used in dim lights to change the intensity of light.

Also Read: Difference Between Viscometer And Rheometer

Differences Between Potentiometer And Rheostat In Tabular Form

BASIS OF COMPARISON POTENTIOMETER RHEOSTAT
Description A potentiometer is a resistor with three terminals and a sliding contact with an adjustable voltage divider.   A rheostat is a variable resistor with two terminals that forms connection with one end and the wiper or slider only.  
Use A potentiometer is used as a measuring instrument or component in electronics.   Rheostat is used to vary the resistance of a circuit.  
Makeup A potentiometer is made of resistive elements such as graphite, resistance wire, cermet and carbon particles.   Rheostat is made of various materials such as fluids, metal ribbon and carbon disk.  
Function Potentiometer is mainly used in circuits to vary voltage or to give variable supply voltage.   Rheostat is mainly used in circuits to vary current.  
Main Function The main function of potentiometer is to vary voltage or voltage dividing.   The main function of rheostat is to control the flow of current.  
Application A potentiometer has low power and is used for audio devices, television control and as a transducer.   A rheostat is used in high power electronics and appliances such as mixers, fans, motors and motors of large industrial machines.  
Connection The potentiometer is connected in parallel with the circuit.   Rheostat forms a serial connection with the circuit through which the flowing current is to be controlled.  
Flexibility Potentiometer can be used as a rheostat.   A rheostat cannot be used as a potentiometer.  
Voltage Dividing Rheostat cannot divide voltage.   A potentiometer can divide voltage.  

Also Read: Difference Between Colorimeter And Spectrophotometer