potentiometristä

Potentiometer (Finnish: potentiometri) is an electrical component that functions as a variable resistor. It is commonly used as a position sensor, a voltage divider, and as a means of controlling analog devices such as volume controls in audio equipment. In a standard potentiometer the resistance between two terminals changes linearly with the rotation of a knob or movement on a linear track, while the third terminal provides a moving contact that samples the voltage across the resistive element. The total resistance of the element is usually specified, and the moving contact, known as the wiper, divides this resistance into two parts that vary in inverse proportion as the wiper is moved. When one terminal is connected to a voltage source and the other two terminals serve as the input and output of a signal line, the output voltage is directly proportional to the position of the wiper, creating a voltage divider.

Potentiometers come in many forms, including rotary, linear, magnetic, and optical variants. Rotary potentiometers have a circular resistive track and are driven by turning a shaft, while linear potentiometers use a straight track and are moved by sliding a stylus. Magnetic potentiometers replace the physical wiper with a magnetic resonance system, offering higher durability and precise positioning without mechanical contact. The choice of resistive material—such as carbon, metal film, or wire—affects the device’s temperature stability, noise performance, and lifespan.

Applications of potentiometers extend beyond simple audio controls. In instrumentation, they are used for calibration, as a touch-sensitive input for controllers, and as a component of analog-to-digital converters. They are also employed in automotive systems for throttle position sensing, in industrial controls for adjusting variable load or speed, and in electronic hobbyist projects due to their versatility and low cost. Key specifications for selecting a potentiometer include resistance value, tolerance, load rating, mechanical life, and operating temperature range.