Balancing arrangement for signals from e.g. combustion oximeter - uses fixed and adjustable resistors having good thermal coupling and equal and opposite dependence on temp.

摘要

A sensor (10) of 02 concn. is connected to a control unit (20) by three wires (11-13) through a plug (15) incorporating a fixed resistor (40) and an adjustable resistor (30). At the control unit (20) the adjustable resistor (30) is earthed directly, and the fixed resistor (40) via a current-measuring device (50) pref. having negligible internal resistance. The resistors (30, 40) are placed close together so as to experience the same temp. in all operating conditions. USE/ADVANTAGE - In e.g. diesel engine exhaust systems, temp. drift is prevented by simple circuit which allows probe to be replaced without re-adjustment.