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Variable resistor – a special electronic component in the PCBA process


The variable resistor is an essential electrical and electronic component. It is different from normal resistor because it allows you to control voltage or current flow by hand. The most common applications for the variable resistor are volume controls on audio equipment and display brightness on TVs, computer screens, or other consumer electronics.

What are a variable resistor and its types?

What-are-a-variable-resistor-and-its-typesA variable resistor is an adjustable resistor consisting of a resistor body and a sliding system. It allows us to control the amount of resistance in an electrical circuit. The most common type of variable resistor is called a rheostat, which you can find at any hardware store.

The main types of variable resistors are rheostats, potentiometers, and trimmers.

1) Rheostats: These are the simplest type of variable resistor, also called “resistance coils.” They use a coil of wire to control the flow of current through the device by varying the resistance in the circuit. They are commonly used as volume controls in stereos and other audio equipment.

2) Potentiometers: Pots are a type of rheostat that features a sliding contact (wiper) that moves over a resistive material or coating. This resistor is most often used where the circuit current needs to be regulated or the resistance of the circuit needs to be changed. They can also be used for controlling brightness on an LED light fixture or dimming lights using PWM (pulse-width modulation).

3) Trimmers: Trimmers are essentially miniature potentiometers that feature three terminals instead of two (like a pot), giving them more flexibility regarding how they can be used. Trimmers come in all shapes and sizes; one common application is using them as voltage dividers in oscilloscopes and signal generators.

What is a variable resistor symbol?

resistor-symbolThe arrow on the left side signifies that the device can change its resistance. The two horizontal lines represent the two terminals of the resistor, and the circle represents the resistor’s body. The numbers inside of the circle are called ohms (Ω).

What are the features of variable resistors?

• They can create variable voltage, variable current, and variable resistance.
• Their value varies with the applied voltage.
• Variable resistors are used in circuits where the physical size of a resistor needs to be changed.
• Variable resistors are made from a thin strip of metal that has been etched with a pattern of stripes.
• The resistance of a variable resistor can be adjusted by sliding a movable contact along the strip.
• The farther you move the contact away from its starting position, the higher its resistance becomes.

What is the range of variable resistors?

The range of a variable resistor is the difference between its highest and lowest values. The range of a resistor is usually expressed in ohms but can also be expressed in other units such as kΩ (kilo ohms), MΩ (mega ohms), or GΩ (Giga ohms).

What is a variable resistor used for?

The most common use of variable resistors is in volume controls. These knobs you see on your stereo, and television sets, allow you to adjust how loud or soft the sound is.

Another common application for variable resistors is potentiometers (potentiometers), whose function is to regulate the amount of voltage (including DC and signal voltage) and current.

Variable resistors can also be used to create a sensor that detects temperature changes or pressure changes in a room.

How is a variable resistor made?

Variable resistors are made from many materials, including carbon, ceramics, metal alloys, and semiconductors. Some resistors are designed to be adjusted by rotating a knob or screwdriver, while others have sliding contacts that allow you to change their resistance by moving them up or down.

The main components of a variable resistor are:

An insulating material called the body forms the case of the resistor. The body may also act as one terminal of the resistor. The most common body material is ceramic.

A wire coil or strip forms the other terminal of the resistor and any other terminals needed for connecting wires from other components in your circuit. The wire coil is wound around a magnetic rod known as an armature mounted inside the resistor’s body.

What are the five types of resistors?


Fixed resistors

These are the most common type of resistors. They have a fixed value of resistance that never changes. The color bands on the resistor indicate the importance of resistance and tolerance.

Variable resistors

As mentioned above, these are also known as rheostats or potentiometers and allow you to control a voltage by varying its resistance. They can be used to adjust the brightness of an LED or control the volume on your stereo system.

Carbon composition resistors

Carbon composition resistors use carbon granules as their resistive element instead of wire coils or solid bars of metal oxide like other types of resistors do. Because they have so much surface area compared to their size, they can dissipate a lot more heat than different types of resistors without melting down!

Wirewound resistors

Wirewound resistors are made from long thin wires wrapped around an insulating core (usually ceramic or mica). This type of construction gives them very high power ratings.

Metal oxide film resistors

Metal oxide film resistors are made from solutions of hydrolysable metal salts (such as tin tetrachloride and antimony trichloride) that decompose on the surface of hot glass or ceramics. The performance of the resistors varies considerably depending on the manufacturing conditions. They have a high tolerance, good stability and temperature characteristics, high reliability, and long life. They are widely used in all types of electronic equipment.

FAQ about variable resistor

FAQ about variable resistor

What is the difference between a fixed resistor and a variable resistor?

The main difference between a fixed resistor and a variable resistor is that the latter can be adjusted. This makes them very useful in circuits where you want to control current flow or voltage, for example.

For example, you can use a variable resistor if you need to control the amount of current flowing through a circuit. A fixed resistor doesn’t have this ability, so if you want to own something like the brightness of an LED, then you need to use a variable resistor instead.

What are the common variable capacitors?

There are many variable capacitors; one of the most common is the air-variable capacitor. Air-variable capacitors have a coil and a plate that move in and out of a metal box to change the capacitance of the capacitor.

The plates are connected to the positive and negative terminals on the variable capacitor, so when you turn it, you’re moving the plates closer together or farther apart. This changes how much charge can fit into your capacitor. The more charge you can fit in there, the more voltage it can store up.


The variable resistor is an electronic component that determines the amount of current flowing through a circuit to make connections between components. It is a three-pin device, composed of a wiper connector and two end connectors.

Also known as a potentiometer, variable resistors are used in radio tuning circuits, volume controls at radios and audio systems, dimmer switches in light controls, volume controls on audio amplifiers, and airport runway lighting panels.



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