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Difference Between Rheostat and Potentiometer
Rheostats and potentiometers are both electrical components that allow for current adjustment. However, they differ in terms of design, construction, and operation.
A potentiometer is a three-terminal resistor that is used to measure or change the voltage in a circuit. A rheostat is an electrical component that uses resistance to control the flow of current in a circuit.
Read this article to find out more about Rheostats and Potentiometers and how they are different from each other.
What is Rheostat?
A rheostat is an electrical component that uses resistance to control the flow of current in a circuit. It is a variable resistor, which means that its resistance may be adjusted by moving a contact over a fixed resistance element. Rheostats are commonly used in electrical systems that require precise regulation of current flow, such as power supplies, light dimmers, and motor speed controls.
Controlling the brightness of a light bulb is one of the most popular uses for a rheostat. The amount of current flowing through the circuit can be adjusted by connecting a rheostat in series with the bulb, allowing the brightness of the bulb to be varied. Rheostats are also used to control motor speed, heat, and voltage in electronic circuits.
It needs to be noted that rheostats have various limitations. They generate heat as current passes through them because they are essentially resistors, and this can lead them to overheat and burn out if they are not properly rated for the application. In addition, since the resistance of the coil is limited, rheostats are not suitable for high-power applications, and huge currents might cause excessive heating and damage to the device.
Rheostats are used in a variety of applications, including lighting systems, where they control the intensity of light, and motor speed controllers, where they regulate motor speed. They are also used to control the flow of current in circuits in scientific experiments.
What is Potentiometer?
A potentiometer is a three-terminal resistor that is used to measure or change the voltage in a circuit. A variable resistor or voltage divider is another name for it. A resistive element, a wiper, and two end terminals make up a potentiometer. The wiper is a sliding contact that slides along the resistive element, which is commonly a long, coiled wire or a carbon track. The voltage between the two end terminals can be adjusted by shifting the location of the wiper.
Potentiometers are used in a variety of electrical applications, including audio volume and tone controls, lighting dimmer switches, and motor speed control in robotics. They are also used to detect voltage and current in scientific equipment.
A potentiometer's resistive element usually consists of a resistive material such as carbon, cermet, or conductive plastic. The wiper is usually constructed of conductive material such as brass or nickel and is connected to a moving contact arm. The potentiometer's two end terminals are connected to the resistive element's ends.
When a voltage is applied between the potentiometer's two end terminals, a voltage drop is formed across the resistive element. The amount of voltage dropped across the resistive element can be adjusted by moving the wiper along it, and the voltage output between the wiper and one of the end terminals can be controlled.
Potentiometers have limitations. Because of the sliding motion of the wipers, they are susceptible to wear and tear, which can lead them to become scratchy or noisy over time. They also have a restricted range of resistance and current handling capabilities, making them unsuitable for high-power applications.
Difference between Rheostat and Potentiometer
The following table highlights the major differences between Rheostat and Potentiometer −
Characteristics |
Rheostat |
Potentiometer |
|---|---|---|
Number of terminals |
2 |
3 |
Resistance range |
Higher |
Lower |
Current handling capacity |
Higher |
Lower |
Voltage handling capacity |
Lower |
Higher |
Linear/Logarithmic taper |
Linear |
Linear or logarithmic |
Typical applications |
Motor speed control, heating applications, regulating current |
Volume and tone controls in audio equipment, lighting dimmer switches, measuring voltage |
Construction |
coil of wire wound around a ceramic or porcelain core |
Resistive element with a wiper that moves along it. |
Function |
variable resistance to control current |
variable voltage divider to control voltage |
Connection |
Serial |
Parallel |
Usage |
It is used to vary resistance. |
It is used to measure instruments. |
Conclusion
While both rheostats and potentiometers can regulate electrical current, rheostats accomplish this by changing the resistance of a circuit, whereas potentiometers measure or adjust the voltage in a circuit.
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