Impedance measuring apparatus

Claim 1

APPARATUS FOR MEASURING THE IMPEDANCE VALUE AND THE PHASE ANGLE OF AN UNKNOWN IMPEDANCE COMPRISING, IN COMBINATION, A SOURCE OF OSCILLATIONS COMPRISING A GENERATOR HAVING ONE TERMINAL THEREOF GROUNDED, AN INPUT NETWORK ENERGIZED FROM THE OTHER TERMINAL OF SAID GENERATOR AND INCLUDING TWO BRANCH CIRCUITS, ONE BRANCH CIRCUIT INCLUDING A REFERENCE IMPEDANCE EMBODIED IN A FIRST FIXED RESISTANCE VOLTAGE DIVIDER ANDTHE OTHER BRANCH CIRCUIT INCLUDING A SECOND VOLTAGE DIVIDER FORMED OF THE UNKNOWN IMPEDANCE TO BE MEASURED AND A FIRST STANDARD IMPEDANCE, SAID BRANCH CIRCUIT PRODUCING AT THE OUTPUTS OF SAID VOLTAGE DIVIDERS TWO SIGNALS PROPORTIONAL RESPECTIVELY TO THE IMPEDANCE VALUES OF SAID REFERENCE IMPEDANCE AND SAID UNKNOWN IMPEDANCE, TWO IDENTICAL AMPLIFICATION CHANNELS CONTROLLED BY SAID SIGNALS OF SAID BRANCH CIRCUITS, RESPECTIVELY, A RATIOMETER CONNECTED TO BE ENERGIZED BETWEEN SYMMETRICAL POINTS ON SAID TWO CHANNELS FOR INDICATING THE RATIO OF THE AMPLIFIED SIGNALS IN SAID TWO CHANNELS, A PHASE METER HAVING TWO INPUTS ENERGIZED RESPECTIVELY FROM THE OUTPUTS OF SAID AMPLIFICATION CHANNELS AND INDICATING THE RELATIVE PHASE SHIFT BETWEEB THE SIGNALS IN SAID TWO CHANNELS PRODUCED BY THE UNKNOWN IMPEDANCE CONNECTED IN ONE OF SAID BRANCH CIRCUITS, A THIRD VOLTAGE DIVIDER FORMED OF FIXED-RESISTANCE OF DIFFERENT RESISTANCE VALUES FROM SAID FIRST FIXED-RESISTANCE DIVIDER, A SECOND STANDARD IMPEDANCE OF A DIFFERENT VALUE FROM SAID FIRST STANDARD IMPEDANCE, AND A MULTIPLE-CONTACT SWITCH FOR ESTABLISHING IN ONE POSITION THEREOF THE CONNECTIONS OF SAID FIRST AND SECOND DIVIDERS IN SAID BRANCH CIRCUITS AND, IN ANOTHER POSITION THEREOF CONNECTING SAID SECOND FIXEDRESISTANCE DIVIDER IN SAID OTHER BRANCH CIRCUIT INSTEAD OF SAID SECOND VOLTAGE DIVIDER, AND SIMULTANEOUSLY CONNECTING SAID UNKNOWN IMPEDANCE AND SAID SECOND STANDARD RESISTANCE IN A FOURTH VOLTAGE DIVIDER CONNECTION IN SAID ONE BRANCH CIRCUIT, AND DISCONNECTING SAID FIRST FIXED-RESISTANCE DIVIDER, SAID UNKNOWN IMPEDANCE AND SAID SECOND STANDARD RESISTANCE BEING REVERSED IN POSITIONS IN SAID FOURTH VOLTAGE-DIVIDER CONNECTION FROM THE POSITIONS OCCUPIED BY SAID UNKNOWN IMPEDANCE AND SAID FIRST STANDARD IMPEDANCE IN SAID SECOND VOLTAGE DIVIDER CONNECTION.