Negative feedback amplifier for bridge-type transducers

Claim 1

A TRANSDUCER AMPLIFIER CONFIGURATION COMPRISING: A VOLTAGE DIVIDER INCLUDING FIRST AND SECOND IMPEDANCE BRANCHES CONNECTED IN SERIES BETWEEN FIRST AND SECOND TERMINALS, SAID FIRST IMPEDANCE BRANCH INCLUDING FIRST AND SECOND IMPEDANCE ELEMENTS CONNECTED IN SERIES, SAID FIRST IMPEDANCE ELEMENT HAVING A MAGITUDE WHICH IS SUBSTANTIALLY LESS THAN SAID SECOND IMPEDANCE ELEMENT AND BEING COUPLED TO SAID FIRST TERMINAL, SAID SECOND IMPEDANCE ELEMENT BEING COUPLED TO A JUNCTION BETWEEN SAID FIRST AND SECOND IMPEDANCE BRANCHES, AND AT LEAST ONE OF SAID IMPEDANCE BRANCHES INCLUDING A VARIABLE IMPEDANCE ELEMENT; A SOURCE OF FIRST POTENTIAL AND A SOURCE OF SECOND POTENTIAL CONNECTED IN SERIES BETWEEN SAID FIRST AND SECOND TERMINALS, SAID FIRST AND SECOND POTENTIALS HAVING A VOLTAGE RATIO WHICH IS NORMALLY EQUAL TO THE IMPEDANCE RATIO OF SAID FIRST AND SECOND IMPEDANCE BRANCHES; AN AMPLIFIER HAVING INPUT AND OUTPUT TERMINALS; MEANS FOR CONNECTING SAID INPUT TERMINALS BETWEEN A JUNCTION OF THE SOURCES OF FIRST AND SECOND POTENTIAL AND A JUNCTION OF THE FIRST AND SECOND IMPEDANCE BRANCHES SUCH THAT A VOLTAGE IS DEVELOPED ACROSS SAID INPUT TERMINALS WHEN THE VOLTAGE RATIO-IMPEDANCE RATIO EQUALITY IS MODIFIED BY VARIATION OF SAID VARIABLE IMPEDANCE ELEMENT AND SUCH THAT AN OUTPUT SIGNAL IS DEVELOPED BETWEEN SAID OUTPUT TERMINALS WHICH IS A DIRECT FUNCTION OF THE VARIATION OF SAID VARIABLE IMPEDANCE ELEMENT; AND MEANS FOR APPLYING A PORTION OF SAID OUTPUT SIGNAL ACROSS SAID FIRST IMPEDANCE ELEMENT TO DEVELOP A NEGATIVE FEEDBACK VOLTAGE BETWEEN THE INPUT TERMINALS OF SAID AMPLIFIER.