Direct reading bridge circuit

Claim 1

A DIRECT READING BRIDGE CIRCUIT FOR MEASURING IMPEDANCE COMPRISING: A STANDARD IMPEDANCE; AN UNKNOWN IMPEDACE HAVING ONE TERMINAL CONNECTED TO SAID STANDARD IMPEDANCE; A COMPLEMENT IMPEDANCE INCLUDING A VARIABLE IMPEDANCE, CONNECTED TO THE OTHER TERMINAL OF SAID UNKNOWN IMPEDANCE TO FORM A FIRST SERIES CIRCUIT WITH SAID STANDARD IMPEDANCE, SAID UNKNOWN IMPEDANCE AND SAID COMPLEMENT IMPEDANCE; A FIRST RATIO ARM IMPEDANCE INCLUDING A VOLTAGE DIVIDER POTENTIOMETER, SAID FIRST IMPEDANCE HAVING ONE TERMINAL CONNECTED TO SAID COMPLEMENT IMPEDANCE; A SECOND RATIO ARM IMPEDANCE HAVING ONE TERMINAL CONNECTED TO SAID STANDARD IMPEDANCE AND ANOTHER TERMINAL CONNECTED TO THE OTHER TERMINAL OF SAID FIRST IMPEDANCE SO THAT SAID SECOND IMPEDANCE IS CONNECTED IN SERIES WITH SAID FIRST IMPEDANCE TO FORM A SECOND SERIES CIRCUIT WHICH IS CONNECTED IN PARALLEL WITH SAID FIRST SERIES CIRCUIT; A VOLTAGE SOURCE CONNECTED ACROSS BOTH OF SAID SERIES CIRCUITS; NULL DETECTOR MEANS FOR INDICATING A BALANCED BRIDGE CIRCUIT; MEANS FOR CONNECTING SAID NULL DETECTOR MEANS IN A BALANCE POSITION IN A CIRCUIT EXTENDING FROM A POINT BETWEEN SAID STANDARD IMPEDANCE AND SAID UNKNOWN IMPEDANCE TO A POINT BETWEEN SAID FIRST IMPEDANCE AND SAID SECOND IMPEDANCE, AND FOR CONNECTING SAID NULL DETECTOR MEANS IN A READ POSITION IN A CIRCUIT EXTENDING FROM A POINT BETWEEN SAID COMPLEMENT IMPEDANCE AND SAID UNKNOWN IMPEDANCE TO THE MOVABLE CONTACT OF SAID VOLTAGE DIVIDER OF SAID FIRST IMPEDANCE; MEANS FOR VARYING SAID COMPLEMENT IMPEDANCE TO CHANGE THE SERIES IMPEDANCE OF SAID FIRST SERIES CIRCUIT TO BALANCE SAID NULL DETECTOR MEANS IN SAID BALANCE POSITION; AND MEANS FOR VARYING THE MOVABLE CONTACT OF SAID VOLTAGE DIVIDER OF SAID FIRST RATIO IMPEDANCE WHILE MAINTAINING THE SERIES IMPEDANCE OF SAID FIRST AND SECOND SERIES CIRCUITS CONSTANT TO BALANCE SAID NULL DETECTOR IN SAID READ POSITION TO ENABLE THE SETTING OF SUCH MOVABLE CONTACT TO PROVIDE A DIRECT READOUT OF THE VALUE OF SAID UNKNOWN IMPEDANCE.