Differential temperature measurements in engine fluids Available to Purchase

IN AIRCRAFT TESTING, it has been difficult to accurately determine small differential temperatures in mediums such as engine oils and aircraft fuels which may vary in temperature over several hundred degrees. A method of measuring this temperature with an electronic circuit utilising platinum probes is presented which is capable of measuring temperature differentials as low as 2.5°C. This method utilises two platinum element probes connected in series driven by a constant current generator. An electronic circuit holds the mid‐point of the probes at virtual ground minimising common mode voltages across the probes. A differential amplifier provides an output proportional to the differential temperature. The mis‐matching and non‐linearity of the platinum sensors is compensated. Voltage sensed across one probe provides an output proportional to the temperature of the medium.