Fluke 752A – Reference Voltage Divider

The Fluke 752A is a precision DC voltage divider engineered for high-accuracy calibration applications requiring ppm-level uncertainties. It delivers two fixed division ratios - 10:1 and 100:1 - with output uncertainties of ±0.2 ppm and ±0.5 ppm respectively. The instrument incorporates Dynamic Resistor Matching™ and an internal calibration bridge to maintain ratio stability across temperature and time.

Self-calibration takes approximately five minutes using only a stable source and null detector, with no external standards required. The calibration procedure compensates for long-term resistor drift by switching divider elements through Wheatstone bridge configurations. When paired with a 10 V reference source and null detector, the 752A functions as a 5-decade voltage calibrator, enabling direct comparison of input voltages from 0.1 V to 1000 V against a precision reference.

Internal switching eliminates manual lead reconfiguration during multi-range calibration work.

Technical Specifications

Division Ratios and Accuracy

• 10:1 ratio: ±0.2 ppm output uncertainty (0 V to 100 V input)


• 100:1 ratio: ±0.5 ppm output uncertainty (0 V to 1000 V input)


• Null accuracy: ±0.5 µV (10:1), ±1.0 µV (100:1)


• Specifications valid for ±1 °C thermal variation from calibration temperature (18 °C to 28 °C) for up to 8 hours post-calibration


• Temperature coefficient: < ±1 ppm/°C operating range; typically 0.1 ppm/°C (15 °C to 30 °C) Electrical Characteristics


• Input resistance: 380 kΩ ±1% (10:1); 2 MΩ ±1% (100:1)


• Maximum input: 200 V (10:1 ratio), 1100 V (100:1 ratio)


• Power coefficient: ≤0.05 ppm of output at 100 V (10:1); ≤0.3 ppm of output at 1000 V (100:1)

Key Features

• Two fixed ratios with internal switching for instant ratio selection


• Self-calibration capability without external standards


• Dynamic Resistor Matching™ for enhanced long-term stability


• Built-in calibration bridge for independent verification


• Low null detection sensitivity: 0.5 µV and 1.0 µV resolution

Typical Applications

• High-precision DC voltage metrology and standards traceability


• Multi-range voltage calibrator systems when integrated with reference sources


• Voltage divider ratio verification and characterization


• Temperature-controlled calibration environments

Compatibility & Integration

• Works with Fluke 732B 10 V reference source for complete calibrator systems


• Operates with any stable DC source and null detection instrument