A variable resistor, also known as a variable resistor or variable resistor, is an electronic component that allows users to manually adjust the resistance value in a circuit. Adjustable resistors are typically used to adjust the current, voltage, or power of a circuit, or as sensors to detect position, speed, or other physical quantities. Adjustable resistors are mainly divided into two types: potentiometers and trimmers.

Potentiometer:

A potentiometer is the most common type of adjustable resistor, which has a knob or sliding rod that changes the resistance value by rotating or sliding. The potentiometer has three leads, with two fixed leads connected to the two ends of the resistor element, and a third moving lead (usually referred to as a cursor or sliding contact) connected to the middle position of the resistor element. When the cursor moves, it changes the effective resistance value in the circuit.

Potentiometers are widely used in volume and tone control of audio devices, calibration and setting of electronic devices, and other applications that require continuous adjustment of resistance.

Trimmer Potential:

Trimming resistor is a small, infrequently adjustable resistor commonly used for internal adjustment of circuit boards. They usually do not have external knobs, but are adjusted through a small screwdriver or other tool. The adjustment of fine-tuning resistors is usually carried out during manufacturing or maintenance to accurately calibrate circuit parameters.

The size of fine-tuning resistors is smaller than that of ordinary potentiometers, making them suitable for applications with limited space, and their adjustment is not frequent, making them more suitable for situations that do not require frequent user intervention.

characteristic:

Adjustable: Adjustable resistors allow users to change the resistance value in the circuit as needed.

Linear or logarithmic characteristics: Potentiometers can have linear (linear variation) or logarithmic (logarithmic variation) resistance characteristics to adapt to different application requirements.

Multiple packaging: Adjustable resistors come in various packaging forms, including axial leads, radial leads, surface mount (SMD), etc.

Rated power: Adjustable resistors have different power levels, and users need to choose the appropriate rated power according to the needs of the circuit.

Application:

Volume and tone control: Used in audio equipment to adjust the size and tone of sound.

Brightness adjustment: Used in displays and lighting equipment to adjust brightness.

Calibration and adjustment: Used in electronic devices to calibrate circuit parameters such as gain, bias, etc.

Sensor: Used as a position or speed sensor in certain applications.

Variable resistors or potentiometers come in various packages and sizes, suitable for different applications and installation methods. Here are some common packaging types and their size descriptions:

1. Axial lead potentiometer:

Size: The diameter ranges from a few millimeters to tens of millimeters, and the length is usually between a few millimeters to tens of millimeters.

Features: Two leads are led out from both ends of the resistor body, suitable for through-hole mounting.

2. Radial lead potentiometer:

Size: The diameter and length are similar to the axial lead potentiometer, but the lead is led out from the side.

Features: Suitable for perforated installation, sometimes also used for surface mount (SMT).

3. Panel Mount potentiometer:

Size: Various sizes, depending on application requirements, usually with threads or buckles for fixation on the panel.

Features: Designed for direct installation on the device's panel, convenient for users to operate.

4. Trimmer Potentiometers:

Size: Very small, with a diameter typically ranging from a few millimeters to a dozen millimeters, and a correspondingly small length.

Features: Designed for fine tuning on circuit boards, usually requiring a screwdriver for adjustment.

5. Surface mount (SMD/SMT) potentiometers:

Size: Very small, with size codes such as 0402, 0603, 0805, 1206, etc., each representing a specific length and width.

Features: Suitable for automated surface mounting processes, without the need for leads, directly soldered to circuit boards.

6. Multi turn potentiometers:

Size: There are various sizes, but they are usually slightly larger than single turn potentiometers because more mechanical structures are needed to achieve multi turn adjustment.

Features: Allow for finer adjustments, usually used for applications that require high-precision adjustments.

7. Wirewound potentiometers:

Size: Larger in size, especially for power type wire wound potentiometers, as they require sufficient space to wrap resistance wires.

Features: It can withstand high power and is commonly used in industrial and automotive applications.

When selecting adjustable resistors, in addition to considering packaging and size, factors such as resistance range, accuracy, power, operating force, durability, and environmental adaptability also need to be considered. Manufacturers usually provide detailed product specifications and data sheets to help users make appropriate choices. Due to the wide variety of adjustable resistors, the most suitable adjustable resistor product should be selected based on specific circuit design and application requirements.