A Two‐Wire IC Compatible Capacitive Transducer Circuit

The important features of the transducer bridge circuit considered here are that under certain conditions the circuit output can be made relatively independent of (1) changes in the carrier period, (2) changes in branch resistance, and (3) changes in capacitances due to temperature. Additional features are (4) the circuit is located at the transducer and (5) requires only two connecting leads to the necessary energizing and indicating equipment, and (6) the branch containing the transducer can be balanced by a pure resistor in the other branch. Each of these features is important for integrated circuit considerations. Some pressure transducer assemblies incorporating a hybrid integrated circuit version of the circuit bridge are shown in addition to sample calibrations.