Motion detecting transducer

Claim 1

IN A DEVICE FOR DETECTING MOVEMENT AND PRODUCING A SIGNAL PROPORTIONAL THERE THE COMBINTION COMPRISING, A PRIMARY WINDINGS, A SOURCE A A.-C. POWER CONNECTED TO APPLY EXCITATION CURRENTS TO SAID PRIMARY WINDING, A SECONDARY WINDING, A MOVABLE CORE OF MAGNETIC MATERIAL, MEANS FOR CONNECTING SAID WINDINGS TO PROVIDE AN A.-C. DIFFERENCE SIGNAL ACROSS SAID SECONDARY WINDINGS, SAID SECONDARY WINDING BEING POSITIONE WITH RESPECT TO THE FIELDS GENERATED BY SAID PRIMARY WINDING SO THAT SAID DIFFERENCE SIGNAL IS ZERO WHEN SAID CORE IS IN A NEUTRAL POSITION, SAID CORE BEING MOVABLE IN RESPONSE TO MOVEMENTS TO BE DETECTED TO PRODUCE AN A.-C. DIFFERENCE SIGNAL OF MAGNITUDE AND PHASE PROPORTIONAL TO THE MAGNITUDE AND DIRECTION OF MOVEMENT OF SAID CORE FROM SAID NEUTRAL POSITION, SAID A.-C. SOURCE PROVIDING SIGNALS OF SUFFICIENT MAGNITUDE TO GENERATE EXCITATION CURRENTS IN SAID PRIMARY WINDING WHICH WILL SATURATE SAID CORE ON EACH HALF CYCLE OF SAID SIGNAL THROUGHOUT THE RANGE OF MOVEMENT OF SAID CORE TO THEREBY MAKE SAID DIFFERENCE SIGNAL INSENSITIVE TO VARIATIONS IN MAGNITUDE OF SIGNALS FROM SAID A.-C. SOURCE.