Impedance measuring apparatus

Claim 1

AN IMPEDANCE-MEASURING DEVICE COMPRISING, IN COMBINATION: AN IMPEDANCE LOOP INCLUDING FIRST AND SECOND ELEMENTS OF KNOWN INPEDANCE CONNECTED IN SERIES, MEANS FOR CONNECTING A THIRD ELEMENT OF UNKNOWN IMPEDANDE IN SAID LOOP IN SERIES WITH SAID FIRST AND SECOND IMPEDANCE ELEMENTS, A VOLTAGE DIVIDER HAVING THREE TERMINALS AND A CONSTANT INPUT IMPEDANCE BETWEEN ITS FIRST AND SECOND TERMINALS, SAID VOLTAGE DIVIDER HAVING ITS FIRST AND SECOND TERMINALS CONNECTED BETWEEN SAID FIRST AND THIRD ELEMENTS, MEANS FOR VARYING THE RELATIVE INTERNAL IMPEDANCE OF SAID DIVIDER SO THAT ITS TRANSFER RATIO VARIES, A TERMINAL AT THE JUNCTION BETWEEN SAID FIRST AND SECOND ELEMENTS WHICH, TOGETHER WITH THE THIRD TERMINAL OF THE VOLTAGE DIVIDER, COMPRISES A SECOND PAIR OF TERMINALS, A THIRD PAIR OF TERMINALS COMPRISING A TERMINAL AT THE JUNCTION OF SAID SECOND AND THIRD ELEMENTS AND THE TERMINAL OF SAID DIVIDER CONNECTED TO SAID FIRST ELEMENT, A VOLTAGE SOURCE CONNECTED BETWEEN ONE OF SAID SECOND AND THIRD PAIRS OF TERMINALS, MEANS RESPONSIVE TO THE VOLTAGE BETWEEN THE OTHER OF SAID SECOND AND THIRD PAIRS OF TERMINALS, AND A LINEAR SCALE COUPLED TO SAID VOLTAGE DIVIDER TO INDICATE THE TRANSFER RATIO OF THE VOLTAGE DIVIDER.