A Semiautomatic Calorimeter for Measurement of Effective Efficiency of Thermistor Mounts

A calorimeter for the direct measurement of effective efficiency of transfer standard thermistor mounts is described. Since calorimetric determination of effective efficiency is insensitive to mismatch error and since the number of steps in the calibration procedure are reduced from usual practice, it is possible to provide an improved accuracy of calibration. Furthermore, since calibration at several frequencies can be performed in a reasonable time without removing the thermistor mount from the calorimeter, this improvement in accuracy can be realized across the bandwidth of the thermistor mount. The response time constant of the calorimeter is 1.5 min for a representative thermistor mount. The results of the calibration are displayed as an X-Y plot of effective efficiency versus frequency.