DIFFERENTIAL (PUSH-PULL) DISPLACEMENT SENSOR
Differential (Push-Pull) Displacement Sensor
Where the two end plates are fixed and the middle plate is attached to a moving object whose displacement (dx) needs to be measured.
Suppose that the capacitor plates are connected to the bridge circuit, forming the reactance’s Z3and Z4.
If initially the middle plate is placed at an equal separation of x from the end plates, and then the middle plate is moved by dx, we have
A linear push-pull displacement sensor.
This is a convenient linear relation for the displacement.