The MODEL DT 72A DEKATRAN DECADE TRANSFORMER is a laboratory standard divider for establishing either voltage or current ratios at audio frequencies. The DEKATRAN circuit is an auto-transformer with a variable tap. The tap position is indicated by the dial reading which gives the ratio of output turns to input turns. Additional windings extend the ratio above and below the input so that voltage ratios of -0. 1 and +1. 1 are available. The accuracy of the DEKATRAN is established by intercomparisons over a wide range of frequencies and dial settings, traceable to a special NBS -certified transformer.