Multivibrator utilizing magnetoresistive elements

Claim 1

A MULTIVIBRATOR CIRCUIT COMPRISING FIRST AND SECOND FERRO-MAGNETIC THIN FILMS HAVING MAGNETORESISTIVE PROPERTIES IN WHICH THE ELECTRICAL RESISTANCE OF THE FILM CHANGES DEPENDS ON THE ORIENTATION OF THE MAGNETIC LINES OF FORCE OF A MAGNETIC FIELD RELATIVE TO THE DIRECTION OF CURRENT FLOW THROUGH SAID FILM, FIRST AND SECOND ELECTRICAL BRIDGE CIRCUITS ASSOCIATED WITH SAID FIRST AND SECOND FILMS RESPECTIVELY, MEANS FOR ENERGIZING EACH OF SAID BRIDGE CIRCUITS, EACH OF SAID THIN FILMS BEING CONNECTED AS ONE LEG OF THE ASSOCIATED BRIDGE, FIRST AND SECOND COIL MEANS FOR PROVIDING A BIASING MAGNETIC FIELD TO SAID FIRST AND SECOND FILMS RESPECTIVELY, SAID FIRST BIASING MEANS ARRANGED TO CAUSE THE RESISTANCE OF SAID FIRST FILM TO BE OF A FIRST MAGNITUDE AND SECOND BIASING MEANS BEING ARRANGED TO CAUSE THE RESISANCE OF SAID SECOND FILM TO BE OF A SECOND MAGNITUDE, FIRST AND SECOND CONTROL COIL MEANS FOR SAID FIRST AND SECONG FILMS RESPECTIVELY, SAID COIL MENS BEING ENERGIZABLE AND ARRANGED FOR PROVIDING A CONTROL MAGNETIC FIELD TO THE ASSOCIATED FILM WHICH COUNTERACTS THE EFFECT OF THE ASSOCIATED BIASING MAGNETIC FIELD, MEANS COUPLING THE COIL MEANS ASSOCIATED WITH EACH FILM ACROSS THE BRIDGE CIRCUIT OF THE OTHER FILM, AND MEANS FOR ENERGIZING SAID FIRST CONTROL COIL MEANS TO PROVIDE A CONTROL MAGNETIC FIELD TO CAUSE THE RESISTANCE ACROSS SAID FIRST FILM TO CHANGE AND TO CAUSE THE VOLTAGE ACROSS SAID FIRST BRIDGE CIRCUIT TO CHANGE CORRESPONDINGLY, AND MEANS FOR COUPLING THE OUTPUT OF SAID FIRST BRIDGE CIRCUIT TO SAID SECOND CONTROL COIL MEANS ASSOCIATED WITH SAID SECOND FILM WHEREBY SAID SECOND COIL MEANS PROVIDES A CONTROL MAGNETIC FIELD TO CAUSE THE RESISTANCE ACROSS SAID SECOND FILM TO CHANGE AND TO CAUSE THE VOLTAGE ACROSS SAID SECOND BRIDGE CIRCUIT TO CHANGE CORRESPONDINGLY, AND MEANS FOR COUPLING THE OUTPUT OF SAID SECOND BRIDGE CIRCUIT TO SAID FIRST CONTROL COIL MEANS WHEREBY A FREE RUNNING BISTABLE OPERATION IS OBTAINED.