A Potentiometer is a commonly used electronic component that controls the voltage, current or signal strength in a circuit by manually adjusting and changing the resistance value. The following is its detailed description:
1. Basic structure
Resistor body: Usually made of carbon film, metal film, conductive plastic or winding material, it provides a continuous resistance path.
Sliding contact (brush) : Connected to a rotatable or sliding shaft, it comes into contact with the resistor body and changes the effective resistance value.
Pin/terminal
Both ends: Fixed ends (connect the two ends of the resistor body).
The third terminal: Sliding terminal (output variable voltage or voltage divider signal).
2. Main types
Rotary potentiometer: Adjusted by a knob (such as volume control).
Linear sliding potentiometer: Adjusted by linear sliding (such as a dimmer).
Multi-turn potentiometer: It needs to be rotated multiple times to complete full-range adjustment, with higher precision.
Digital potentiometer: Controlled by digital signals (such as I²C interface), without mechanical contacts.
Switch potentiometer: Integrated switch function (like the volume switch of an old-fashioned radio).
3. Key parameters
Resistance range: Common ones include 1kΩ, 10kΩ, 100kΩ, etc. They are marked as nominal resistance values (for example, "B10K" indicates linear 10kΩ).
Resistance value variation characteristics
Linear (Type B) : The resistance value has a linear relationship with the rotation Angle (formula: R = kθ).
Logarithmic (Type A) : Suitable for volume control (human ear logarithmic response).
Index (Type C) : Contrary to Type A, it is less common.
Rated power: Usually 0.1W to 2W. Exceeding this range may cause overheating and damage.
Resolution: The resolution of wound potentiometers is relatively low, while that of conductive plastics is relatively high.
Mechanical life: Carbon film is approximately 10,000 times, while conductive plastic can reach 500,000 times.
4. Working Principle
Voltage division mode: As a three-terminal device, the input voltage is applied across both ends, and the sliding terminal outputs voltage division (formula: Vout = Vin × (R2 / (R1 + R2))).
Variable resistance mode: Only the sliding end and one end are used as variable resistors.
5. Application scenarios
Analog signal regulation: Audio equipment (volume, pitch), dimming circuits.
Calibration circuit: Adjust the sensor sensitivity or amplifier gain.
User input control: game controller, instrument panel knob.
6. Precautions for Selection
Environmental factors: The sealed model is dust-proof and moisture-proof, and industrial-grade high-temperature resistant.
Installation methods: PCB installation, panel installation or with casing.
Precision requirements: Multi-turn potentiometers are suitable for fine-tuning, while ordinary knobs are used for rough adjustment.
7. Frequently Asked Questions
Noise: Poor contact caused by aging of the carbon film or oxidation of the contacts is manifested as noise or signal jumping.
Mechanical wear: Frequent adjustments may reduce the lifespan. It is necessary to choose a model with high durability.
Load effect: Connecting a low-impedance load to the output terminal will cause the voltage division to be nonlinear.
8. Symbols and Annotations
Circuit symbol: A resistor with an arrow indicates an adjustable terminal.
Model marking: For example, "RK09" indicates a certain series of rotary potentiometers.
A Potentiometer is a commonly used electronic component that controls the voltage, current or signal strength in a circuit by manually adjusting and changing the resistance value. The following is its detailed description:
1. Basic structure
Resistor body: Usually made of carbon film, metal film, conductive plastic or winding material, it provides a continuous resistance path.
Sliding contact (brush) : Connected to a rotatable or sliding shaft, it comes into contact with the resistor body and changes the effective resistance value.
Pin/terminal
Both ends: Fixed ends (connect the two ends of the resistor body).
The third terminal: Sliding terminal (output variable voltage or voltage divider signal).
2. Main types
Rotary potentiometer: Adjusted by a knob (such as volume control).
Linear sliding potentiometer: Adjusted by linear sliding (such as a dimmer).
Multi-turn potentiometer: It needs to be rotated multiple times to complete full-range adjustment, with higher precision.
Digital potentiometer: Controlled by digital signals (such as I²C interface), without mechanical contacts.
Switch potentiometer: Integrated switch function (like the volume switch of an old-fashioned radio).
3. Key parameters
Resistance range: Common ones include 1kΩ, 10kΩ, 100kΩ, etc. They are marked as nominal resistance values (for example, "B10K" indicates linear 10kΩ).
Resistance value variation characteristics
Linear (Type B) : The resistance value has a linear relationship with the rotation Angle (formula: R = kθ).
Logarithmic (Type A) : Suitable for volume control (human ear logarithmic response).
Index (Type C) : Contrary to Type A, it is less common.
Rated power: Usually 0.1W to 2W. Exceeding this range may cause overheating and damage.
Resolution: The resolution of wound potentiometers is relatively low, while that of conductive plastics is relatively high.
Mechanical life: Carbon film is approximately 10,000 times, while conductive plastic can reach 500,000 times.
4. Working Principle
Voltage division mode: As a three-terminal device, the input voltage is applied across both ends, and the sliding terminal outputs voltage division (formula: Vout = Vin × (R2 / (R1 + R2))).
Variable resistance mode: Only the sliding end and one end are used as variable resistors.
5. Application scenarios
Analog signal regulation: Audio equipment (volume, pitch), dimming circuits.
Calibration circuit: Adjust the sensor sensitivity or amplifier gain.
User input control: game controller, instrument panel knob.
6. Precautions for Selection
Environmental factors: The sealed model is dust-proof and moisture-proof, and industrial-grade high-temperature resistant.
Installation methods: PCB installation, panel installation or with casing.
Precision requirements: Multi-turn potentiometers are suitable for fine-tuning, while ordinary knobs are used for rough adjustment.
7. Frequently Asked Questions
Noise: Poor contact caused by aging of the carbon film or oxidation of the contacts is manifested as noise or signal jumping.
Mechanical wear: Frequent adjustments may reduce the lifespan. It is necessary to choose a model with high durability.
Load effect: Connecting a low-impedance load to the output terminal will cause the voltage division to be nonlinear.
8. Symbols and Annotations
Circuit symbol: A resistor with an arrow indicates an adjustable terminal.
Model marking: For example, "RK09" indicates a certain series of rotary potentiometers.
