Electrical sensors are intended to determine charge, current, potential,
potential difference, electric field (amplitude, phase, polarization,
spectrum), conductivity and permittivity and, as such, have some
overlap with magnetic sensors. Power measurement, an important
measure of the behavior of many manufacturing processes, is also included
here. An example of the application of thermal sensors for
true root-mean-square power measurement was included with the
discussion on thermal sensors. The use of current sensors (perhaps
employing principles of magnetic sensing technology) is commonplace
in machine tool monitoring. Electrical resistance measurement
has also been widely employed in tool wear monitoring applications.
Most of the discussion on magnetic sensors below is applicable here
in consideration of the mechanisms of operation of electrical sensors.