The John Fluke Model 752A is a self-calibrating, precision dc voltage divider with two ranges of division: 10:1 and 100:1. In addition to the two divider ranges, the 752A incorporates switching modes used in the cardinal point calibration of dc voltage calibrators. The points provided on the 752A are 0.1V, IV, 10V, 100V, and 1000V. When the 752A is combined with a dc voltage calibrator, a 10V reference standard, and a null detector, the 752A switches the equipment to standardize the dc voltage calibrator without having to physically change the leads. 1-3. The 752A is self-calibrated before each use. This procedure requires a stable source and a null detector. The 752A is a ratio device only, and does not have to be included in a calibration cycle that is traceable to an external standard. 1 -4. The front panel MODE switch selects between self- calibration and normal operation. In the Self-Calibration mode, the voltage divider resistors are compared using an external null detector to an internal, self-calibrating bridge to precisely set their overall value, and hence, the division ration of the 752A. The three push-to-tum CALIBRATE controls adjust the 10:1 divider, 100:1 divider, and the self-calibration bridge. The CALIBRATE switch selects the divider to be calibrated and interchanges the two resistors in the self-calibration bridge to check that they are of equal value. If not, the BALANCE control adjusts one of these resistors by a small amount to make both selfcalibration bridge resistors equal in value. 1-5. In normal operation, the MODE switch settings correspond to the cardinal calibration points of a dc voltage calibration system. The MODE switch now interconnects the external equipment in one of three ways (refer to Figure 2-3): 1. The voltage divider of the 752A is connected between the reference standard and the null detector as shown in Figures 2-3a and 2-3b. 2. The voltage divider is out of the circuit and the reference standard is compared directly with the UUT (unit under test) as shown in Figure 2-3c. 3. The voltage divider is connected between the UUT and the null detector as shown in Figures 2-3d and 2-3 e.