The term potentiometer is derived from the old established method of obtaining a precise division of a potential (a voltage), by using a resistance wire.
The fraction of the supply voltage that is obtained at the output is proportional to the length AB of the wire if the wire is of uniform cross-sectional area. This use of a resistor requires two fixed connections and one variable connection, so that any variable resistor with three connections became known as a potentiometer.
In some applications, the resolution of a potentiometer may need to be known. The resolution is the smallest alteration in resistance that can be achieved, and is usually expressed as a percentage. For example, a resolution of 1% would imply that 100 separate steps of division ratio could be achieved, and for a 1 kΩ linear potentiometer this would imply that the change of resistance in each step was 10 Ω.
The materials that are used for the resistive tracks of potentiometers and trimmers are the same as those used for fixed resistors. Carbon composition tracks have lingered rather longer in potentiometer production than on fixed resistors, but the predominant technology is now the cermet track.
Types of potentiometers:
- carbon-track potentiometers
- slide potentiometers
- carbon presets
- cermet potentiometers
- multi-turn cermets
- conductive plastic potentiometers
- wire-wound potentiometers
- potentiometer lows or tapers
04-12-2009, 09:54 AM
Potentiometer
Linear Mode
