The accuracy and reliability gap between an RTD and a thermocouple may be close to being closed thanks to research being performed at Electronic Development Labs Inc., Danville, Va. By combining two traditional devices, thermocouples and transformers, EDL has extended the accuracy of a differential temperature measurement. Currently, obtaining measurement accuracies below 0.1oC requires sophisticated equipment. The new measurement technology uses a transformer to accomplish the gain required to make low level direct current measurements, improving signal-to-noise ratios. The input signal from the -thermocouple is synchronously modulated with a second input to form the primary side of the transformer, which acts as the first stage amplifier. Input impedances are low and the modulation rate is slow enough to minimize the adverse effects of Johnson Noise. The second input acts as a balancing circuit to the thermocouple input; together, they form a null balancing system that is capable of canceling built-in systematic error.

EDL expects that commercializing the technology, for which patents have been applied, will be as challenging as defining the areas of engineering and science that can benefit.

EDL's research and calibration laboratory, under the direction of Kenneth Sloneker, has received funding support through the Virginia Center for Innovative Technology, Herndon, Va., and is jointly developing an advanced prototype with the Technology Applications Center at Old Dominion University, Norfolk, Va.