How does a capacitive encoder work?

A capacitive encoder works by measuring the change in capacitance from the change in dimensions of the capacitor. A capacitive encoder uses the change in capacitance value of a capacitor as a means to measure displacement. Typically, the capacitive sensor’s principle elements are arranged so that the capacitance changes as a moving elements displace relative to the stationary plates of the capacitor.

How does a capacitive encoder work

  1. Typically comprises of three main elements; a transmitter, conductive plates separated by a non-conductive material and a receiver board.
  2. Capacitance varies in proportion to the distance of the plates (d), as well as their overlap (A).
  3. Displacement can be measured axially (variation in d) or in the planar direction of the plate overlap (variation in A).

Strengths and weaknesses of a capacitive encoder

Compact, low powerSignificant temperature & humidity conflicts, sensitive to foreign matter.