The nomenclature of modern electronics is densely populated by various potentiometers, trimmers, and resistors that operate largely on the same basic premise: they help monitor or control the voltage or current that passes through an electrical system. Among the most fundamental of these electrical components is resistance; a double-ended passive component with a predefined electrical resistance. This is essential for inhibiting current flow, terminating transmission signals, and other uses. A practical limitation of the ubiquitous resistance is the constancy of the electrical resistance of the material, 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 generally performed by 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 to divide voltage and measure electrical potential are known as potentiometers.
What is a potentiometer?
Potentiometers are manually adjustable variable resistors, commonly known as speed potentiometers or potentiometers. They function as variable voltage dividers where the output voltage is determined by the position of the wiper. Standard single-turn potentiometers have been used as simple measurement and control for voltage output in electrical systems, but modern circuits often require a more precise solution.
Precision potentiometers are designed for monitoring and control applications where precision and reliability are of the utmost importance. Precision single or multi-turn potentiometers are available, allowing tighter control of voltage parameters without having to compromise with the complex integration of multiple standard potentiometers in a network of compound dividers.
Construction of precision potentiometers
There are several formats of precision potentiometers, but the most recognizable construction is the rotary format that features a resistive element connected to a circular windshield wiper and then to a shaft. Two terminals in the circuit are connected to each end of the element, the resistance of which is determined by the position of the wiper. The shaft controls the position of the windshield wiper through a mechanical user interface; usually an adjustable dial.
The method used here is simple: if the amperage in a circuit is constant, the value of the resistance directly affects the voltage used. Increasing the resistance has a direct impact on the voltage output according to Ohm's Law. Precision potentiometers use materials with strong linearity to ensure extremely high resolutions, which refers to the smallest possible change in the resistance ratio of the material.
Precision potentiometers can comprise any number of materials and types of resistors, including the composition of carbon, conductive plastic, metallic film, or wound elements. Precision conductive plastic potentiometers have the highest known resolution, although this can be affected by the wiper setting and the number of contact points.
Precision potentiometers from TT Electronics
TT Electronics specializes in developing novel electrical solutions for your application, offering a range of precision potentiometers with essentially infinite resolution capabilities. If you'd like to find out how we've accomplished this, simply contact a member of the TT Electronics team today.