电位器是一种可调的电子元件。它是由一个电阻体和一个转动或滑动系统组成，当电阻体的两个固定触电之间外加一个电压时，通过转动或滑动系统改变触点在电阻体上的位置，在动触点与固定触点之间便可得到一个与动触点位置成一定关系的电压。 它大多是用作分压器，这是电位器是一个四端元件。电位器基本上就是滑动变阻器，有几种样式，一般用在音箱音量开关和激光头功率大小调节。 　　初中电学实验中常用的滑动变阻器就是一种常见的线绕电位器。

             The potentiometer is an adjustable electronic components. It is composed of a resistor and a rotating or sliding system, when the resistance body between two fixed contacts and a voltage, by rotating or sliding system change the contact in the resistor body position, the moving contact and the fixed contact can be a movable contact position with a certain relationship voltage. It is mostly used as a voltage divider, the potentiometer is a four terminal element. The potentiometer is basically a sliding rheostat, there are several styles, generally used in speaker volume switch and the first laser power adjust. Junior Electrical experiment used sliding rheostat is a common wire wound potentiometer.

        选择旋转式电位器的几项原则：在高频、高稳定性的场合，选用薄膜电位器。要求高精度的场合，选用线绕多圈电位器。要求高分辨率的场合，选用各类非线绕电位器，多圈微调电位器。普通应用场合，选用碳膜电位器。要求电压均匀的变化场合，选用直线式电位器。音量控制宜选用指数式电位器。

       Selection of rotary potentiometers several principles: in high frequency, high stability of the occasion, choose the film potentiometer. The requirements of high precision of the occasion, selection of wire wound multiturn potentiometer. High resolution of the occasion, the selection of various types of non - wirewound potentiometers, multiple circle trimming potentiometer. Common applications, selection of carbon film potentiometer. Required voltage fluctuation occasions, selection of linear potentiometer. Volume control to choose the index type potentiometer.