Description
Technical Specifications
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Model: SRB-31
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Type: Standard Resistance Box / Reference Standard
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Accuracy:
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±0.2% from 1 mΩ to 100 kΩ
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±0.5% below 1 mΩ
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Resistance Range: 20 µΩ to 100 kΩ
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Total Steps: 25 fixed resistance values
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Resistor Material: Manganin wire coils
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Temperature Coefficient: ~0.000002 / °C (virtually zero temp. coefficient)
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Decade Type: Resistance
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Switch Type: Rotary / selector switch operation
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Applications: Reference standard calibration, power-electronics testing, meter verification, R&D, QA, and educational laboratories
📋 Resistance Values
20 µΩ, 100 µΩ, 150 µΩ
1 mΩ, 1.5 mΩ, 2 mΩ, 10 mΩ, 15 mΩ
100 mΩ, 150 mΩ, 200 mΩ
1 Ω, 1.5 Ω, 2 Ω
10 Ω, 15 Ω, 20 Ω
100 Ω, 150 Ω, 200 Ω
1 kΩ, 1.8 kΩ, 2 kΩ
10 kΩ, 100 kΩ
⚡ Maximum Current Ratings
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20 µΩ – 250 A
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100 µΩ – 125 A
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150 µΩ – 100 A
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1 mΩ – 50 A
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1.5 mΩ – 30 A
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2 mΩ – 20 A
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10 mΩ – 15 A
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15 mΩ – 6 A
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100 mΩ – 3 A
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150 mΩ – 2 A
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200 mΩ – 1.5 A
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1 Ω – 1.25 A
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1.5 Ω – 1.0 A
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2 Ω – 1.0 A
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10 Ω – 0.6 A
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15 Ω – 0.6 A
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20 Ω – 0.5 A
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100 Ω – 0.12 A
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150 Ω – 0.12 A
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200 Ω – 0.10 A
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1 kΩ – 10 mA
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1.8 kΩ – 10 mA
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2 kΩ – 9 mA
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10 kΩ – 3 mA
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100 kΩ – 1.5 mA
📘 Product Overview
The Standard Resistance Box SRB-31 is a high-precision laboratory reference instrument designed to deliver ultra-low to mid-range resistance values from 20 micro-ohms to 100 kilo-ohms across 25 fixed resistance steps. It provides outstanding stability and repeatable accuracy using manganin wire resistance coils, known for their near-zero temperature coefficient (0.000002 /°C) to ensure consistent resistance values regardless of thermal changes.
With an accuracy of ±0.2% for 1 mΩ to 100 kΩ, and ±0.5% below 1 mΩ, the SRB-31 is ideally suited for high-current measurement verification, milliohm testing, calibration of digital multimeters, bridges, power-equipment testing, and low-resistance standardization tasks.
Its rugged construction and smooth switching mechanism enable safe operation even at extremely high current ratings up to 250 A at micro-ohm ranges, making it indispensable for calibration labs, energy research facilities, transformer and cable testing units, electronics R&D centers, and technical institutes.
⭐ Key Features
✅ Wide range: 20 µΩ to 100 kΩ
✅ 25 precise resistance steps
✅ High stability manganin coils
✅ Ultra-low temperature coefficient for drift-free performance
✅ High current capacity up to 250 A
✅ ±0.2% precision across main resistance range
✅ Ideal reference standard for calibration & testing
