(a) Describe, with the aid of a sketch, the principle and operation of a potentiometer.(6)
(b) Explain how a potentiometer can be used to measure rotary movement.(4)
Potentiometer: Principle and Operation
A potentiometer is essentially a variable resistor with three terminals. It works on the principle of voltage division.
1. Potentiometer – Analog Devices
2. Potentiometer Working Principle With Their Types And Applications – BYJU’S
Components of a Potentiometer:
- Resistive Element: A conductive material (often wire or carbon) wound around an insulating core.
- Wiper: A sliding contact that moves along the resistive element. 1. The Complete Guide to Potentiometers – DigiKey www.digikey.com
- Terminals: Three terminals: one at each end of the resistive element and one connected to the wiper. 1. Potentiometer Guide – Phidgets Support www.phidgets.com
Operation:
- Voltage Application: A voltage is applied across the two fixed terminals of the potentiometer.
- Wiper Movement: The wiper can be moved along the resistive element, changing its position. 1. Basic Principles of Potentiometers/Variable Resistors | doEEEt.com www.doeeet.com
- Voltage Division: As the wiper moves, it divides the total resistance of the element into two parts: the resistance between the wiper and one end, and the resistance between the wiper and the other end. 1. Potentiometer Brief Theory: Definition, Operating Principle, Types, and Sizing – PCB Basic Information – PCBway www.pcbway.com
- Output Voltage: The voltage at the wiper terminal is proportional to the position of the wiper along the resistive element. 1. Potentiometer Guide – Phidgets Support www.phidgets.com
In essence, a potentiometer allows you to control the output voltage by adjusting the position of the wiper.
1. Potentiometer Guide – Phidgets Support
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potentiometer
Applications:
Position control: In robotics and automation, potentiometers can be used to measure the position of mechanical components.
Volume control: In audio systems, potentiometers are used to adjust the volume. 1. A Complete Guide to Potentiometers – RS Components uk.rs-online.com
Voltage dividers: To create specific voltage levels from a higher voltage source. 1. Voltage Dividers: Operations and Functions | Advanced PCB Design Blog | Cadence resources.pcb.cadence.com
Sensor input: Used in conjunction with other sensors to convert physical quantities (like light, temperature, or position) into electrical signals.
Using a Potentiometer to Measure Rotary Movement
A rotary potentiometer is specifically designed to measure angular displacement or rotation.
1. All You Need to Know About Potentiometers – CUI Devices
Operation:
- Resistive Element: It has a resistive element arranged in a circular or arc-shaped pattern. 1. Rotary potentiometer – definition of term and interesting facts – ALDERS electronic GmbH alders.de
- Wiper: A movable contact, or wiper, is attached to a shaft that rotates along the resistive element. 1. All You Need to Know About Potentiometers – CUI Devices www.cuidevices.com
- Output: As the shaft rotates, the wiper moves along the resistive element, changing the resistance between the wiper and one end of the potentiometer.
- Voltage Division: This change in resistance results in a corresponding change in output voltage.
Key points:
- The output voltage is directly proportional to the angular position of the shaft.
- Rotary potentiometers can provide continuous feedback on the angular position of a rotating object.
- They are often used in applications where precise control or measurement of rotation is required. 1. Rotary Potentiometers: Precision Control for Electronic Applications – ETI Systems etisystems.com
By carefully calibrating the potentiometer, it’s possible to accurately measure angles and rotational speeds.