The DT72A Decade Transformer Standard is a laboratory standard, transformer-type ac decade voltage divider having 0.1 ppm resolution with a seven-dial readout. Direct-reading current division with very high accuracy can also be achieved. The accuracy of each transformer is verified by precise calibration tests. The primary standard of voltage division is a special NBS calibrated transformer divider. DEKATRAN? linearity is established by comparison with this divider. Tests show linearity of the DT72A to be about 0.1 ppm at 400Hz
