Resistors are divided into variable resistors, fixed resistors, special resistors, RJ-type metal film resistors, RT-type carbon film resistors, chip resistors, RX-type wire-wound resistors, high-power resistors, and low-power resistors. Toggle switch The manufacturer introduces the functions of adjustable resistors.

1. Current division
　　When a resistor and another component such as a light bulb are connected in parallel in a circuit, the voltage across the resistor is the same as the voltage across the light bulb, and the current through the resistor plus the current through the light bulb equals the total current through both. Therefore, the resistor serves the function of current division.

2. Voltage division
　　When a resistor and another component such as a light bulb are connected in series in a circuit, the current through the resistor and the light bulb is the same, and the sum of the voltages across the resistor and the light bulb equals the total voltage across them as a whole. Therefore, the resistor serves the function of voltage division.

3. Special resistors
　　Special resistors are made from semiconductor materials, and their resistance values can also change. However, unlike variable resistors, whose resistance can be manually adjusted, the resistance of special resistors depends on external environmental factors. For example, the resistance of a thermistor decreases as temperature increases; it is used in circuits to detect temperature and serve as a thermal sensor. The resistance of a photoresistor significantly decreases under light exposure and can be used as a light switch in circuits. The resistance of a varistor changes with the voltage across it and can protect circuits from voltage fluctuations. Another very special resistor is the superconductor component, which produces no heat when conducting electricity. When used in computer components, it does not require a cooling system, greatly reducing the size and energy consumption of computers.

4. Variable resistors
　　Variable resistors, also called potentiometers, refer to resistors whose resistance values can change. This variability determines their value. For example, in some instrument and meter simulation circuits, there are sometimes uncertain factors that require the potentiometer's variability to adjust the circuit to the optimal state.