PERFORMANCES indicators CHANGES DEVICES physical factors

摘要

Improvements in devices to indicate changes in the physical factors, including a method for indicating a significant variation in a physical factor with which is associated an appreciable change in value of the dielectric constant, a strip of material required to have a negligible variation of said physical factor throughout its length, comprising the steps of passing the strip, or a longitudinal section chosen thereof, between the plates of a capacitor test, using the change in the capacitance test resulting from the significant change in the value of the dielectric constant of the strip material passing therethrough for influencing the operation of an electronic control circuit, and make a resultant variation in said electronic control circuit to cause the operation indicator means appropriate.