Non-self generating transducer signal conditioning technique

This paper presents an approach to signal conditioning of resistance type transducers that provides improved accuracy under adverse conditions encountered in airborne and field testing as well as simplified calibration requirements. The technique involves using a dual tracking constant current circuit to supply the bridge power and measuring the differential IR drops across the elements. The bridge in this case, is really a Y circuit composed of two series branches with a common node. In this configuration the two current sources are connected to the tips of the Y and the IR drops between the supplies and the supply common are measured. The common node is connected to the power supply common. The change in IR drop (delta R) is a linear representation of the physical phenomenon at the transducer plus the lead wire effects, and since the circuit is symmetrical in every respect it requires only three wires to implement any conventional bridge circuit with complete lead wire effect cancellation.