Pressure sensor e.g. for vehicle engine combustion chamber - contains movable structure acting on piezoelectric transducer which is in series with dielectric having capacitance of opposite temp. characteristic wrt transducer

摘要

The sensor contains a movable structure (13,15,17) which is moved according to the applied pressure and a piezoelectric transducer (20) against which a pressure is exerted by the structure when moved. The transducer has opposed electrodes, between which a voltage is generated when the pressure is applied. The capacitance between the electrodes increases with temp.. The capacitance between the electrodes of a dielectric element (21) near the transducer decreases with increasing temp.. The dielectric element and the transducer are connected in series. USE/ADVANTAGE - E.g. for use in vehicle engine combustion chambers. Compact transducer can be used with simple control unit.