722-D

The General Radio 722-D Precision Capacitor was introduced in Catalog J (1936) and remained available through Catalog P (1959).

The Type 722-D is a laboratory quality, dual section, precision variable capacitor. The capacitor is supplied with a wooden carrying case fitted.

A direct reading of both sections is obtained from a drum mounted on the rotor shaft.

The rotor is mounted on ball bearings in an aluminum casting driven by a precision worm drive, and is electrically attached to the frame with silver overlay contacts.

The two stators are brought out to separate terminals on the panel with the shared rotor terminal. The rotor terminal is a the same potential as the panel and copper-lined walnut case.

A correction chart is mounted on the panel for that particular capacitor.

Specifications

• Capacitance Range 25 to 100 pF and 100 to 1100 pF
• Dial Accuracy: High Range ±1 pF ±0.1%; Low Range ±0.2 pF ±0.1%
• Maximum Voltage: 1000 V peak

Links

• Experimenter February 1937 describing Types 722
• Experimenter January 1938 describing Types 722
• Experimenter October 1938 describing Types 722

Photos

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• Carrying Case

  Carrying Case

• Carrying Case

  Carrying Case