Transformer-ratio bridge network with precise lead compensation. And its application to the measurement of temperature and temperature difference

The audio-frequency a.c. bridge described is suitable for field and industrial measurements. It incorporates a precise 6-decade ratio-transformer and two separate toroidal transformers for lead compensation. The condition for balance of the bridge is evaluated and optimum design criteria are established. Measurements of the very precise and stable ratio obtained by keeping two platinum-resistance thermometers at the temperature of the triple-point of water (0.01°C) are presented, and the application of the bridge to the precise measurement of temperature and temperature difference is discussed.