The capacitance for a parallel plate capacitor is given by:
C = .0885 eA/d in pF
where e is the relative permittivity, A is the area in sq. cm and d is the separation between the two plates in cm. If the two parallel plates move relative to each other, the distance and area of the plates affecting the capacitance is altered, and a corresponding change in the capacitance occurs. The relationship between capacitance and mechanical displacement for a given system can be determined. Capacitative transducer systems have been used to measure displacements in the micrometer range.
Figure 6 Capacitative plates displacement measurement system 
Return to theIntroduction
Move back toTransducers and their Applications
Move forward toVariable Inductance Transducers
Support for the development of this module was provided by the National Science Foundation and The Cooper Union for the Advancement of Science and Art.
Please send questions or comments to Professor Ron Adrezin or Professor Daniel Raichel.