The Type 1493 Precision Decade Transformer is a highly accurate, adjustabe-ratio transformer. When connected to a suitable ac source, this instrument can be set for any output between -0.1111111 and +1.1111111 times the input voltage. In general, the principal applications of the Type 1493 are the measurement of unknown ratios and the accurate measurement of complex impedances in transformer bridge circuits . Within the se two broad measurement areas , the uses for this precis ion transformer cover a wide range of specific applications.