Description
Specifications
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Model: RG-321
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Application: DC Null Detection for Kelvin Double Bridge, Wheatstone Bridge & Potentiometers
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Power Supply: 220 V AC, 50 Hz (Mains Operated)
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Light Source: 6 V, 0.3 A torch bulb (Branded)
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Optical System: Mirror-coil with reflected light beam
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Scale Length: 150 mm
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Scale Division: 30 – 0 – 30 with center zero
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Zero Adjustment: Top-mounted zero adjusting knob
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Sensitivity: Up to 2 µA per small division
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Sensitivity Control: 2-pole, 6-way switch (D, 1/10, 1/100, 1/1000, S/C)
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Magnet System: Permanent magnet with uniform magnetic field
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Suspension: Taut band suspension system
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Housing: Bakelite cabinet with built-in lamp and scale
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Operation Type: Optical spot reflection measurement
Product Overview
The Spot Reflective Galvanometer (RG-321) is a highly sensitive optical instrument designed to detect extremely small direct currents with exceptional accuracy. It is widely used as a DC null detector in laboratory and calibration applications, including Kelvin Double Bridge setups, Wheatstone bridges, and potentiometers.
The instrument operates on a reliable mains power supply (220 V AC, 50 Hz) and features a built-in lamp and optical scale. A precision mirror mounted on a taut-band suspended moving coil reflects a bright light beam onto the 150 mm scale, enabling sharp and parallax-free readings. This construction ensures high stability, vibration resistance, and fast response.
Sensitivity can be easily adjusted through a 2-pole, 6-way selector switch, allowing the user to adapt measurements for a wide range of experimental requirements. The center-zero scale with 30-0-30 divisions combined with a convenient zero-adjustment knob ensures fast calibration and precise alignment.
Key Features & Benefits
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Highly sensitive detection down to 2 µA per small division
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Clear optical spot display for precise, parallax-free readings
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Adjustable sensitivity ranges via selector switch
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Stable taut band suspension for vibration-proof operation
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Permanent magnetic field for consistent measurement accuracy
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Built-in lamp and scale system enclosed in a durable bakelite case
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User-friendly zero adjustment for quick setup
Applications
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DC null detection in Kelvin Double Bridge (Traditional KDB)
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Wheatstone bridge measurements
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Potentiometer calibration
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Educational laboratories and R&D testing
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Electrical standards verification
We recommend to use Digital Null Detector instead of Spot Reflecting Galvanometer for checking null detection in Kelvin Double Bridge. As Digital Null Detector comes with 1 year warranty period while for Spot Galvo there is not guarantee due to very sensitive coil.
