Potentiometers

Pilot devices provide control and condition monitoring of different types of processes, equipment and machinery in industrial and commercial applications. They are used for communication from a machine to an operator or from an operator to a machine. Pilot devices can be an audio or visual indicator, or an actuator that is used to control the flow of energy to a process. Visual indicators are: pilot lights, signal towers, strobes and beacons. Audio indictors are: buzzers and sounder horns. Actuators are: push buttons, selector switches, toggle switches and potentiometers.

Potentiometers are devices that are used to provide a variable resistance. The most common form is the single turn rotary potentiometer. It varies its resistive value as a result of angular movement. Rotating a dial or knob attached to a shaft causes the internal wiper to sweep around a curved resistive element. An example of a rotary potentiometer is a radio transistor’s volume controller, which when rotated, controls the current supply to the amplifier. Slider potentiometers are designed to change the value of their contact resistance by means of a linear motion. There is a linear relationship between the position of the slider contact and the output resistance.

Potentiometers are a simple way to convert a mechanical position into a proportional voltage, therefore, they are often used as resistive position sensors or linear displacement sensors. Sliding track potentiometers measure a linear motion with the sensor being the resistive element attached to a sliding contact. The contact is attached to a rod or shaft which is then attached to the mechanical mechanism to be measured. The position of the slide changes with respect to the position being measured which in turn changes the resistive value of the sensor.