Inductive Displacement Sensor Circuit

The voltage at the output of circuit 7 depends on the position of the high-permeability core (in blue) which is changed with a mechanical linkage (in red). The output signal must be monitored with a phase-sensitive detector. Here is the figure of the inductive displacement sensor circuit;

There is a null position at the midway point between the two detection coils, which are connected in series-opposition. Commercial devices can have linear ranges from less than 1 mm to more than 250 mm with resolutions of 1 part in 100,000 within the linear range. Inductive displacement transducers can be purchased with integral electronics that internally generates the alternating current and converts the measured signal into a calibrated DC output.