740-B

The General Radio 740-B Capacitance Test Bridge was introduced in Catalog K1 (1939) and remained available through Catalog Q (1961).

The Type 740-B self contained capacitance bridge designed as a service grade instrument. It's self contained with 60 Hz generator derived from it's power transformer. A 6E5 "Eye" tube is used as the null indicator along with a detector sensitivity control. The voltage impressed upon the unknown varies with range switch setting, 35 volts at .0001 μF and 1 volt at the 100 μF settings. The bridge is suitable for testing of paper, mica, and electrolytic capacitors with 1% accuracy.

Specifications

• Capacitance Range: 5 pF to 1100 μF in six ranges
• Capacitance Accuracy: 1% basic accuracy
• Dissipation Range: 0 to 50% in two ranges
• Dissipation Accuracy: 1.5% of full-scale reading for all capacitance multipliers except .0001 range

Links

• Experimenter June 1938 describing Type 740-B
• Experimenter February 1939 describing Type 740-BG
• Experimenter September 1942 describing Type 740-B

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