Transformerless a.c. bridge having a d.c. output

Claim 1

ELECTRICAL MEASURING APPARATUS COMPRISING AN COMBINATION: (1) A BRIDGE NETWORK COMPRISING FIRST, SECOND, THIRD AND FOURTH BRIDGE TERMINALS; A MEASURING IMPEDANCE CONNECTED BETWEEN A FIRST PAIR OF ADJACENT BRIDGE TERMINALS AS ONE ARM OF THE BRIDGE; A REFERENCE IMPEDANCE CONNECTED BETWEEN A SECOND PAIR OF ADJACENT BRIDGE TERMINALS AS A SECOND ARM OF SAID BRIDGE; A BRIDGE OUTPUT TERMINAL; FIRST, SECOND, THIRD AND FOURTH RECTIFYING DEVICES CONNECTED IN CLOSED SERIES IN FRONT-TO-BACK RELATIONSHIP WITH EACH OTHER, THE JUNCTION BETWEEN SAID FIRST AND SECOND RECTIFYING DEVICES BEING CONNECTED TO SAID BRIDGE OUTPUT TERMINAL, THE JUNCTION BETWEEN SAID THIRD AND FOURTH RECTIFYING DEVICES BEING CONNECTED TO SAID FOURTH BRIDGE TERMINAL; A FIRST CAPACITOR CONNECTED BETWEEN SAID FIRST BRIDGE TERMINALS AND THE JUNCTION BETWEEN SAID FIRST AND FOURTH RECTIFYING DEVICES; A SECOND CAPACITOR CONNECTED BETWEEN SAID THIRD BRIDGE TERMINAL AND THE JUNCTION BETWEEN SAID SECOND AND THIRD RECTIFYING DEVICES; AND A THIRD CAPACITOR CONNECTED BETWEEN SAID FOURTH BRIDGE TERMINAL AND THE JUNCTION BETWEEN SAID FIRST AND SECOND RECTIFYING DEVICES;