Adjustable resistance is also called variable resistance. Rheostat is a kind of resistance. Its resistance value can be adjusted artificially to meet the needs of the circuit. The role of adjustable power resistor - can gradually change the current of the electrical appliances in series with it, can gradually change the voltage of the electrical appliances in series with it, and can also play the role of protecting the electrical appliances. In the experiment, it also plays the role of obtaining multiple sets of numerical values.

The adjustable power resistor can be divided into many different types and types according to the magnitude of resistance value, the range of adjustment, the form of adjustment, the manufacturing process, the material of manufacture, the size of volume, etc. It can be divided into carbon film adjustable resistance, ceramic adjustable power resistor, patch adjustable resistance, wire wound adjustable resistance and so on. Common adjustable variable resistor change resistance mainly by changing the length of the resistance access circuit. For temperature-sensitive resistors, they can also change resistance by changing the temperature, which is called thermistor. For light-sensitive resistors, the purpose of changing resistance is achieved by changing the light intensity, which is called photoresistor. In addition, there are piezoresistors, gas-sensitive resistors. And so on. Usually used in small signal circuits, large signal variable resistors are also used in a few occasions such as tube amplifiers.

Potentiometer is a kind of adjustable variable resistor. Usually it is composed of a resistor body and a rotating or sliding system, that is, a moving contact moves on the resistor body to obtain partial voltage output. The function of potentiometer is to adjust the voltage (including DC voltage and signal voltage) and current. The resistor of potentiometer has two fixed ends. By manually adjusting the rotating shaft or sliding handle to change the position of the moving contact on the resistor, the resistance value between the moving contact and any fixed end is changed, thus the magnitude of voltage and current is changed.

Potentiometer is an adjustable electronic element. It consists of a resistor and a rotating or sliding system. When a voltage is applied between the two fixed contacts of the resistor, the position of the contacts on the resistor is changed by rotating or sliding system, and a voltage related to the position of the moving contacts can be obtained between the moving contacts and the fixed contacts. It is mostly used as a voltage divider, when the potentiometer is a four-terminal element. Potentiometers are basically sliding rheostats. Potentiometers come in several styles. Potentiometers commonly used in speaker volume switches and laser head power adjustment are adjustable electronic components. It consists of a resistor and a rotating or sliding system. When a voltage is applied between the two fixed contacts of the adjustable variable resistor, the position of the contacts on the resistor is changed by rotating or sliding system, and a voltage related to the position of the moving contacts can be obtained between the moving contacts and the fixed contacts. Variable resistor for voltage divider. On the bare resistor, one or two movable metal contacts are pressed tightly. The contact position determines the resistance between any end of the resistor and the contact. According to material winding, carbon film, solid core potentiometer; according to the relationship between output and input voltage ratio and rotation angle, linear potentiometer (linear relationship) and functional potentiometer (curve relationship). The main parameters are resistance, tolerance and rated power. Widely used in electronic equipment, volume control in speakers and receivers. Therefore, adjustable resistance can be used frequently in life.