beat-frequency oscillator
Date: circa 1935
Inventory Number: 1997-1-0355
Classification: Oscillator
Manufacturer: General Radio Company (1915-present)
User: Department of Physics, Bowdoin College (founded after 1794)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
64 x 26 x 50 cm (25 3/16 x 10 1/4 x 19 11/16 in.)
Accessories: power cord
Bibliography:
Operating Instructions for Type 713-B Beat-Frequency Oscillator
Description:
This large black box is framed in wood with ventilation panels on top and on the back. The front panel appears to be in plastic or bakelite. Several switches, knobs and dials are used to adjust the output frequency signals. The lower-right dial is a cycles increment dial, useful for obtaining accurate settings at very low frequencies and for obtaining frequencies in the range between 10 and 20 cycles, which are not indicated on the main dial. The latter provides a true logarithmic increase in frequency with angular rotation over the range from 20 to 20,000 cycles per second. The total scale length is approximately 17.5 inches.
On the left side, there is a hole-plug for a seven-foot power cord. The instrument runs on power supply of 110-220 volts or 220-240 volts, 40 to 60 cycles alternating current. The total consumption is about 95 watts. Two handles, one on each side, are used to move this heavy device.
Inside the instrument are several vacuum tubes.
On the left side, there is a hole-plug for a seven-foot power cord. The instrument runs on power supply of 110-220 volts or 220-240 volts, 40 to 60 cycles alternating current. The total consumption is about 95 watts. Two handles, one on each side, are used to move this heavy device.
Inside the instrument are several vacuum tubes.
In Collection(s)
Signedunder central dial: Beat-Frequency Oscillator / Type 713-B Serial No. 735 / General Radio Co. / Cambridge Mass. U.S.A.
Inscribedon a plaque, riveted on wood frame: THIS INSTRUMENT IS LICENSED UNDER PATENTS OF THE AMERICAN TELEPHONE AND TELEGRAPH COMPANY SOLELY FOR UTILIZATION IN RESEARCH, INVESTIGATION, MEASUREMENT, TESTING, INSTRUCTION AND DEVELOPMENT WORK IN PURE AND APPLIED SCIENCE.
in yellow paint: PHYSICS DEPT.
in yellow paint: PHYSICS DEPT.
FunctionAccording to the instruction manual: "The Type 713-B Beat-Frequency Oscillator is an a-c operated device intended for use as a source of alternating current for making tests in the audio-frequency and lower supersonic-frequency ranges. The frequency range of the oscillator is from 10 to 40,000 cycles per second with a logarithmic calibration from 20 to 20,000 cycles per second...
[F]or most practical audio-frequency tests, it is merely necessary to connect the oscillator directly to the line or equipment, making sure that a reasonable impedance match is secured, and then turn the main frequency control over the audio-frequency range and note the reading of an output meter on the equipment under test."
The company claimed that this oscillator would provide high output with low harmonic distortion.
[F]or most practical audio-frequency tests, it is merely necessary to connect the oscillator directly to the line or equipment, making sure that a reasonable impedance match is secured, and then turn the main frequency control over the audio-frequency range and note the reading of an output meter on the equipment under test."
The company claimed that this oscillator would provide high output with low harmonic distortion.
Primary SourcesGeneral Radio Co., Operating Instructions for Type 713-B Beat-Frequency Oscillator (Cambridge, MA, ca. 1935).
ProvenanceCame from the Physics Department of Bowdoin College.