What are variable vs fixed resistors?

 The two primary types of resistors used in electrical circuits are variable and fixed resistors. They vary in resistance value and adjustability:

1、Fixed Resistors:

Fixed resistors have a constant, predetermined resistance value that does not change.

They are designed to have a specific resistance value, which is determined during manufacturing and remains fixed throughout their lifespan.

Fixed resistors are available in various types, including carbon composition, film, wirewound, and thick film resistors.

They are commonly used in electronic circuits for tasks such as current limiting, voltage dividing, biasing, and signal conditioning.

2、Variable Resistors:

Variable resistors, also known as rheostats or potentiometers, have a resistance value that can be adjusted manually or electronically.

They allow for the adjustment of resistance within a certain range, providing variable control over current or voltage levels in a circuit.

There are several varieties of variable resistors, such as trimmers (preset resistors for calibration), digital potentiometers (electro-mechanically controlled variable resistors), rheostats (two-terminal variable resistors), and potentiometers (three-terminal variable resistors).

When exact control over resistance is needed, such as in volume controls, circuit tuning, sensor calibration, and circuit trimming, variable resistors are frequently utilized.

In conclusion, variable resistors have adjustable resistance within a defined range, enabling flexible control over electrical properties in a circuit, whereas fixed resistors have a constant resistance value that never changes.