New capacitive linear and rotary displacement transducers having extremely high both linearity and sensitivity

The basic principle adopted in the design of new transducers is illustrated. This principle is based on the adoption of a very thin dielectric film between the electrodes. The film may be obtained either in micrometrical thickness, 1-3 μm, by a dielectric spray varnish or, as illustrated in the features of an improved design, in submicrometrical, <1 μm, thickness by metallic dielectric deposition in gas phase. The transducers are designed in a differential form. Their electrodes have to be constructed by photochemical etching. Prototypes of the illustrated transducers have been constructed and the test results obtained on them are analyzed. On the basis of the test results obtained, the proposal for a variable absolute capacitor and capacitive voltage divider is presented