Freed-Eisemann model NR-5 radio receiver
date: label: date made
content: c 1923
label: date made
content: 1923
name: label: maker
content: Hazeltine, Louis Alan
label: maker
content: Eisemann Magneto Corp.
notes: label: Description (Brief)
content: Marked: "Neutrodyne Receiver / Model NR-5 / No. 560DD." Instruction sheet mounted below lid. Battery instruction sheet affixed to rear panel. This specimen is an early neutrodyne receiver dating from 1923 and employing five 201-A type tubes. The circuit is essentially a straight triode detector preceded by two stages of radio frequency amplification and followed by two stages of audio. The RF stages have banked coils and are designed to avoid plate-grid capacity feedback. Tuning is accomplished by a variable capacitor in each "neutrostage". The neutrodyne circuit was designed by Louis Hazeltine. This circuit was a strong competitor to Armstrong's superheterodyne. Original price was $150. REF: "Clymer-Greenwood", page 143; "Langley Index", p. 26.
label: Description (Brief)
content: "A significant problem in early radio was the matter of sufficient amplification before the detector stage. Although two or three stages of tuned radio frequency [TRF] amplification were often employed, capacity feedback within the triode tubes then available would often result in undesirable howls or whistles in the loudspeaker. The problem was solved when Louis Alan Hazeltine developed a circuit employing neutralizing capacitors and tilted coils. This Freed-Eismann radio is an early commercial unit employing this circuit."
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from Franklin Wingard
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.320733
label: catalog number
content: 320733
label: accession number
content: 241556
objectType: label: Object Name
content: Receiver
label: Object Name
content: radio receiver
label: Other Terms
content: Receiver; Radio
physicalDescription: label: Measurements
content: overall: 9 in x 28 in x 9 in; 22.86 cm x 71.12 cm x 22.86 cm