18-11-2015, 04:30 PM
The wikipedia entry is pretty good: https://en.wikipedia.org/wiki/Potentiome...trument%29
A potentiometer, as its name implies, is used to measure electrical potential. It does this by comparing a known fraction of one potential with a another potential. If one of the potentials is known (eg a Weston standard cell) then so is the other potential.
There is no current drawn from one of the sources of potential, effectively infinite input impedance.
The modern usage of potentiometer as a 3 terminal variable resistor is simply because it is logically identical to the potential measuring device. Albeit without accurate calibration.
A potentiometer, as its name implies, is used to measure electrical potential. It does this by comparing a known fraction of one potential with a another potential. If one of the potentials is known (eg a Weston standard cell) then so is the other potential.
There is no current drawn from one of the sources of potential, effectively infinite input impedance.
The modern usage of potentiometer as a 3 terminal variable resistor is simply because it is logically identical to the potential measuring device. Albeit without accurate calibration.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
