Semiconductor strain gage transducers

Claim 1

A PRESSURE MEASURING DEVICE COMPRISING (A) A MONOCRYSTALLINE BODY HAVING SURFACE LAYER PORTIONS SEPARATED FROM AN INTEGRAL SUBSTRATE BY A P-N JUNCTION FORMING AN ELECTRICAL CONDUCTIVITY BARRIER, (B) SAID BODY HAVING (1) FIRST AND SECOND OPPOSITE SIDES, AND (2) THIRD AND FOURTH OPPOSITE SIDES TRANSVERSE TO SAID FIRST AND SECOND SIDES, (C) MEANS FORMING A CHAMBER IN SAID BODY AND DISPOSED BETWEEN SAID SIDES, SAID DEVICE MONITORING THE DIFFERENCE IN PRESSURE BETWEEN THE INTERIOR OF SAID CHAMBER AND THE EXTERIOR OF SAID BODY, (D) SAID PORTIONS INCLUDING FIRST, SECOND, THIRD AND FOURTH STRAIN-SENSING PORTIONS CONNECTED IN SERIES IN THE ORDER NAMED BY OTHER LAYER PORTIONS TO FORM A BRIDGE CIRCUIT WITH SAID FIRST AND THIRD STRAIN-SENSING PORTIONS BEING IN OPPOSITE ARMS OF SAID BRIDGE CIRCUIT, (1) SAID FIRST AND THIRD STRAIN-SENSING PORTIONS BEING ON SAID FIRST AND SECOND SIDES, (2) SAID SECOND AND FOURTH STRAIN-SENSING PORTIONS BEING ON SAID THIRD AND FOURTH SIDES, (E) THE SENSITIVE DIRECTION OF SAID LAYER EXTENDING SUBSTANTIALLY ALONG SAID FIRST AND SECOND SIDES, (F) SAID FIRST AND THIRD STRAIN-SENSING PORTIONS EXTENDING IN SAID SENSITIVE DIRECTION.