Heathkit Decade Resistance Model IN-3117

The Heathkit IN-3117 Decade Resistance Box is a precision laboratory instrument for electrical measurement, circuit design, and bridge applications. It delivers selectable resistance values from 1 Ω to 999,999 Ω in 1 Ω increments, with 0.5% accuracy across all ranges. The unit employs shorting-type switches with make-before-break action to ensure smooth, artifact-free resistance adjustment during live measurements.

Minimum terminal resistance at zero is 0.025 Ω, and current handling varies by range - from 1000 mA peak (X1) down to 3 mA peak (X100K), with working currents typically half the maximum. All resistors are rated at 1 watt.

Technical Specifications

• Resistance range: 1 Ω to 999,999 Ω


• Resolution: 1 Ω increments


• Accuracy: 0.5%


• Resistor power rating: 1 W


• Minimum DC terminal resistance: 0.025 Ω


• Maximum current per range: X1 (1000 mA peak, 500 mA working); X10 (300 mA peak, 150 mA working); X100 (100 mA peak, 50 mA working); X1K (30 mA peak, 15 mA working); X10K (10 mA peak, 5 mA working); X100K (3 mA peak, 1.5 mA working)


• Dimensions: 5" H × 7.5" W × 6.625" D


• Net weight: 2.5 lbs

Key Features

• Precision resistors with 0.5% tolerance


• Shorting-type switches with make-before-break contact action


• Compact laboratory footprint suitable for bench and rack integration


• Low residual terminal resistance minimizes measurement error

Typical Applications

• AC and DC bridge circuits


• Variable multiplier or shunt configurations


• Substitution resistance measurement


• Circuit design validation


• Educational and experimental testing


• Calibration and troubleshooting

Compatibility & Integration The IN-3117 operates as a standalone instrument and pairs effectively with Heathkit Decade Capacitance Kits for solving combined resistance and capacitance network problems.