Capacitive bridge transducer system

Claim 1

A TRANSDUCER FOR DETECTING CHANGES IN A MONITORED CONDITION, COMPRISING: A SOURCE OF ALTERNATING CURRENT SIGNALS; A TRANSFORMER HAVING ITS PRIMARY WINDING COUPLED TO THE SOURCE OF ALTERNATING CURRENT SIGNALS AND HAVING A CENTER TAPPED SECONDARY WINDING; A DIFFERENTIAL CAPACITOR HAVING FIRST AND SECOND FIXED PLATES COUPLED TO OPPOSITE TERMINALS OF THE SECONDARY WINDING AND A MOVABLE PLATE CENTRALLY DISPOSED BETWEEN THE FIRST AND SECOND FIXED PLATES; FIRST AND SECOND OUTPUT TERMINALS COUPLED TO THE CENTER TAP AND THE MOVABLE PLATE, RESPECTIVELY, ONE OF SAID OUTPUT TERMINALS BEING CONNECTED TO GROUND REFERENCE POTENTIAL; AND MEANS RESPONSIVE TO SAID SOURCE OF ALTERNATING CURRENT SIGNALS FOR DEMODULATING ALTERNATING CURRENT SIGNALS AT THE OTHER OUTPUT TERMINAL TO DEVELOP A DIRECT CURRENT SIGNAL BETWEEN THE OUTPUT TERMINALS WHICH IS PROPORTIONAL IN MAGNITUDE TO MOVEMENT OF THE MOVABLE PLATE.