A Differential Transformer with Temperature- and Excitation-Independent Output

This paper describes a new concept for compensating for sensitivity changes of a differential transformer due to variations in temperature and excitation conditions. The idea is based on utilization of the individual outputs from the secondary coils, not only as a differential output but also as a reference output. The differential transformer usually has two secondary coils connected in opposition to obtain a differential output. If the voltages induced in the individual secondary coils e1 and e2 are individually taken out and if the operation (e1 - e2)/(e1 + e2), is carried out, then the result becomes independent of temperature and excitation conditions. The experiments, which were made to confirm the effectiveness of this method, gave quite impressive and hopeful results: superior temperature, excitation independence and linearity.