How does a variable resistor (potentiometer) work?
1 Answer
A variable resistor, commonly known as a potentiometer or "pot," is an electrical component that allows you to adjust the resistance along its length manually. It works on the principle of varying the length of the resistive material through which the current passes, thereby changing the resistance and controlling the amount of current flowing through the circuit.
Here's a simplified explanation of how a potentiometer works:
Construction: A typical potentiometer consists of a resistive track (usually made of carbon, cermet, or conductive plastic) that is connected between two fixed terminal points. The resistive track has a uniform resistance per unit length.
Three terminals: A potentiometer has three terminals – two outer terminals and a central terminal (commonly called the wiper). The resistive track spans between the two outer terminals.
Variable resistance: The wiper terminal is connected to a movable contact (a slider or a knob) that can slide along the resistive track. When you turn the knob or move the slider, the wiper changes its position on the resistive track, effectively altering the length of the resistive material through which the current flows.
Resistance adjustment: By varying the position of the wiper along the resistive track, you change the amount of resistive material in the circuit. This, in turn, modifies the resistance between one of the outer terminals and the wiper. The resistance between the wiper and the other outer terminal remains constant.
Voltage division: When you use a potentiometer in a circuit, it acts as a voltage divider. The total resistance between the two outer terminals remains constant, but the amount of voltage dropped across the wiper and one of the outer terminals changes as the wiper position is adjusted. This varying voltage output can be used to control various aspects of the circuit, such as the volume in audio applications, brightness in lamps, or motor speed in motor control circuits.
Linear and logarithmic pots: There are two common types of potentiometers: linear and logarithmic (also known as audio taper). Linear pots provide a uniform change in resistance per unit length of movement, while logarithmic pots are designed to mimic the way human perception of sound volume changes, making them more suitable for audio volume controls.
In summary, a variable resistor (potentiometer) works by allowing you to manually adjust the resistance along its resistive track, which in turn modifies the voltage output and helps control various parameters in electrical circuits.
Here's a simplified explanation of how a potentiometer works:
Construction: A typical potentiometer consists of a resistive track (usually made of carbon, cermet, or conductive plastic) that is connected between two fixed terminal points. The resistive track has a uniform resistance per unit length.
Three terminals: A potentiometer has three terminals – two outer terminals and a central terminal (commonly called the wiper). The resistive track spans between the two outer terminals.
Variable resistance: The wiper terminal is connected to a movable contact (a slider or a knob) that can slide along the resistive track. When you turn the knob or move the slider, the wiper changes its position on the resistive track, effectively altering the length of the resistive material through which the current flows.
Resistance adjustment: By varying the position of the wiper along the resistive track, you change the amount of resistive material in the circuit. This, in turn, modifies the resistance between one of the outer terminals and the wiper. The resistance between the wiper and the other outer terminal remains constant.
Voltage division: When you use a potentiometer in a circuit, it acts as a voltage divider. The total resistance between the two outer terminals remains constant, but the amount of voltage dropped across the wiper and one of the outer terminals changes as the wiper position is adjusted. This varying voltage output can be used to control various aspects of the circuit, such as the volume in audio applications, brightness in lamps, or motor speed in motor control circuits.
Linear and logarithmic pots: There are two common types of potentiometers: linear and logarithmic (also known as audio taper). Linear pots provide a uniform change in resistance per unit length of movement, while logarithmic pots are designed to mimic the way human perception of sound volume changes, making them more suitable for audio volume controls.
In summary, a variable resistor (potentiometer) works by allowing you to manually adjust the resistance along its resistive track, which in turn modifies the voltage output and helps control various parameters in electrical circuits.