Yokogawa 2786 Series Decade Resistance Box

The Yokogawa 2786 Series Decade Resistance Box is a precision instrument for rapid, accurate resistance setting across a wide range of values. Its six-dial configuration enables flexible resistance selection suitable for laboratory, industrial, and production environments. The series is a calibration standard for voltage and current adjustment, functions as a dummy load, and integrates into AC bridge circuits for experimental setups and line testing.

Technical Specifications

• Model 278610: 0.1 Ω to 111,111 Ω


• Model 278620: 1 Ω to 1,111,110 Ω


• Six-dial configuration for intuitive value selection Electrical Performance


• Residual resistance: <23 mΩ


• Temperature coefficient: <±10 ppm/°C


• Accuracy: ±0.01% rdg (at 23±3°C, 45–75% RH, input power 500 MΩ at 500 V DC (panel to circuit)


• Dielectric strength: 1,500 V AC for 1 minute (terminals to case) Power Ratings


• Rated dissipation: 0.3 W per step; 3 W maximum (instrument)


• Maximum allowable input: 0.5 W per step; 5 W maximum (instrument)


• Current limiting: determined by highest-resistance dial when multiple dials are active Environmental


• Operating temperature: 0°C to 40°C


• Storage temperature: -10°C to 50°C


• Humidity range: 25% to 85% RH

Key Features

• Metal case shields against electrical, magnetic, and thermal interference


• Compact form factor: 497 mm (W) × 116 mm (H) × 140 mm (D)


• Weight: approximately 3.5 kg - portable for field and bench use


• Rack-mountable configuration available with case removal


• Overvoltage protection safeguards against element value shift from excessive input

Typical Applications

• Voltage and current standard adjustment in metrology labs


• Dummy load simulation for power supply and amplifier testing


• Component in AC bridge measurement circuits


• Production line resistance calibration and verification


• Experimental circuit development requiring precise, repeatable values