1644-A

The General Radio 1644-A Megohm Bridge is a Megohm Bridge introduced in Catalog S (1965). It remained available through Catalog 1978. It replaced the Type 544-B.

The Type 1644-A is a modified Wheatstone bridge design used for resistance measurements in 9 ranges from 1 kΩ to 1 TΩ. It contains a built-in vacuum tube detector and high voltage power supply. Besides measuring resistors, its uses are measuring semiconductor leakage, capacitor resistance and insulation resistance, for example.

Specifications

• Resistance Range: 1 kΩ to 1000 TΩ in ten decade ranges
• Accuracy: ±1% basic accuracy from 1 kΩ to 10 GΩ (see manual)
• Test Voltages: 10, 20, 50, 100, 200, 500, and 1000 Volts
• Short-Circuit Current: <15 mA at 10 V to 50 V; <10 mA at 100 to 1000 V

Links

• Experimenter describing Type 1644-A December 1964

Photos

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  Detector Board and Foil Side of Power Supply

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  Power Supply Board Close-Up

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  Detector Board Close-Up

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