A. c. transducers and variometers

Claim 1

AN ALTERNATING CURRENT TRANSDUCER DEVICE COMPRISING: FIRST AND SECOND MAGNETIC CORE MEMBERS, EACH HAVING ON ONE FACE THEREOF AN ANNULAR SURFACE CONSISTING OF A SINGLE FLAT PLANE, SAID CORE MEMBERS BEING MOUNTED WITH SAID ANNULAR SURFACES IN OPPOSED PARALLEL RELATION AND ON A COMMON AXIS, SAID SURFACE THUS DEFINING THEREBETWEEN A NORROW ANNULAR AIR GAP; A FIRST ELECTRIC WINDING BONDED FLAT TO SAID ANNULAR SURFACE OF SAID FIRST CORE MEMBER AND INCLUDING AT LEAST A PAIR OF COILS ARRANGED ON OPPOSITE SIDES OF SAID COMMON AXIS, EACH COIL COMPRISING A PLURALITY OF TURNS WOUND ABOUT A COMMON COIL AXIS AND COVERING A SEPARATE SECTORIAL PORTION OF THE ANNULAR SURFACE OF SAID FIRST CORE MEMBER, ADJACENT COILS BEING OPPOSITELY WOUNDED WITH RESPECT TO EACH OTHER AND ALL COILS BEING SERIALLY CONNECTED; A SECOND ELECTRIC WINDING BONDED FLAT TO SAID ANNULAR SURFACE OF SAID SECOND CORE MEMBER AND INCLUDING A PLURALITY OF COILS EQUAL IN NUMBER TO A MULTIPLE OF THE NUMBER OF COILS IN SAID FIRST WINDING, THE COILS OF SAID SECOND WINDING BEING EQUALLY DISTRIBUTED ABOUT SAID COMMON AXIS AND EACH COMPRISING A PLURALITY OF TURNS WOUND ABOUT A COMMON COIL AXIS AND COVERING A SEPARATE SECTORIAL PORTION OF THE ANNULAR SURFACE OF SAID SECOND CORE MEMBER, ADJACENT COILS OF SAID SECOND WINDING BEING OPPOSITELY WOUND AND ALL BEING SERIALLY CONNECTED IN A COMMON CIRCUIT AND MEANS FOR VARYING THE COUPLING BETWEEN SAID FIRST AND SECOND WINDINGS.