The Fluke 721A Lead Compensator is a precision instrument that eliminates measurement errors in voltage-divider circuits caused by lead and contact resistance. By equalizing voltage drops across parallel resistive dividers, it delivers the accuracy demanded in high-precision metrology applications. The 721A functions as an operational accessory for high-accuracy voltage dividers including the Fluke 720A and 725A models, where even small resistance-induced errors compromise results.
## Technical Specifications
• Resistance compensation resolution: 0.1 mΩ
• Maximum divider resistance ratio: 4000:1
• Maximum allowable lead resistance: 150 mΩ
• Maximum divider voltage: 1500 V DC or peak AC
• Fine control: 10-turn, 150 mΩ slide-wire potentiometer
• Coarse control: 18-position rotary switch
• Binding posts: Gold-plated copper
• Voltage switch: Grounds input voltage terminals for thermal voltage compensation
## Key Features
• Two-stage compensation network—coarse adjustment via rotary switch for rapid zeroing, fine adjustment via precision potentiometer for exact nulling.
• 0.1 mΩ resolution enables compensation of minute contact and lead resistances that would otherwise degrade divider accuracy.
• Supports divider resistance ratios up to 4000:1, accommodating diverse measurement configurations.
• Gold-plated binding posts ensure low-resistance connections and long-term reliability in precision circuits.
• Integrated voltage switch permits compensation of thermal EMF without disconnecting the divider.
## Physical Specifications
• Height: 8.8 cm (3.5 inches)
• Width: 48.2 cm (19 inches)
• Depth: 15.2 cm (6 inches)
• Weight: 2.72 kg (6 lb)
## Typical Applications
The 721A is essential in precision voltage measurement and calibration work where contact and lead resistance introduce unacceptable errors. It is particularly suited for high-accuracy metrology requiring milliohm-level compensation and measurements at elevated voltages up to 1500 V.
## Compatibility & Integration
Designed specifically as an operational accessory for the Fluke 720A and 725A high-accuracy voltage dividers.
