The nomenclature of modern electronics is densely populated by various potentiometers, trimmers and resistors that largely operate on the same basic premise: they assist with monitoring or controlling either the voltage or current passing through an electrical system. Among the most fundamental of these electrical components is the resistor; a passive dual-terminal component with a pre-defined electrical resistance. This is essential for inhibiting current flow, terminating transmission signals, and other uses. A practical limitation of the ubiquitous resistor is the constancy of the material’s electrical resistance, which is why variable resistors were developed.
Briefly: A variable resistor, often called a rheostat, is a component with an adjustable electrical resistance; a function that is usually conducted using an integrated wiper contact that adjusts the resistance track of the variable resistor. Measuring instruments that operate on this same basic principle with a third terminal for dividing voltage and measuring electrical potential are known as potentiometers.
What is a Potentiometer?
Potentiometers are manually-adjustable variable resistors commonly referred to as speed pots, or pot meters. They function as variable voltage dividers where the output voltage is determined by the wiper position. Standard single-turn potentiometers have been used as a simple measure and control for voltage output in electrical systems, but modern circuits often require a more accurate solution.
Precision potentiometers are designed for monitoring and control applications where accuracy and reliability are of paramount importance. Both single- and multi-turn precision potentiometers are available, enabling tighter control of voltage parameters without having to commit to the complex integration of multiple standard potentiometers into a compound divider network.
Construction of Precision Potentiometers
Various precision potentiometer formats exist, but the most recognizable construction is the rotary format which features a resistive element connected to a circular wiper then to a shaft. Two terminals in the circuit are connected to either end of the element, the resistance of which is determined by the position of the wiper. The shaft controls the wiper position by means of a mechanical user interface; typically, an adjustable dial.
The method used here is simple: If the amperage in a circuit is constant, the value of resistance directly affects the voltage used. Increasing the resistance has a direct impact on voltage output according to Ohm’s Law. Precision potentiometers employ materials with strong linearity to ensure extremely high resolutions, which refers to the smallest possible change in the material’s resistance ratio.
Precision potentiometers may comprise any number of resistor materials and types, including carbon composition, conductive plastic, metal film, or wirewound elements. Conductive plastic precision potentiometers boast the highest known resolution, though this can be impacted by the wiper configuration and number of contact points.
Precision Potentiometers from TT Electronics
TT Electronics specializes in the development of novel electrical solutions for your application, offering a range of precision potentiometerswith essentially infinite resolution capabilities. If you would like to learn how we have accomplished this, simply contact a member of the TT Electronics team today.