U.S. Army Signal Corps filter box for SCR-68 radio transceiver
date: label: date made
content: 1918
notes: label: Description (Brief)
content: U.S. Army Signal Corps filter box for SCR-68 radio transceiver. Wooden case with controls mounted on front. No maker tag. See schematic inside SCR-68 radio unit. SCR-68 unit comprises a radiotelephone transceiver, a fan-driven generator, a filter box, and an interphone box. Six binding posts appear on the filter box, four for connection to the transceiver and three for connection to the generator. Specimen is inserted in the output circuit of the generator and is designed to eliminate the commutation noises from transmitting and receiving circuits. Two condensers are bridged across the high and low voltage generator leads, and a choke coil and resistor are connected in series with the 4th lead from the box marked "receiver". The lead extending from this terminal forms the positive connection to the filaments of the receiving vacuum tubes. The resistor contained in the filter box limits the current in the receiving tube filaments to the proper value. Ref: SCR-68 Airplane Radio Telephone Set, SCR Pamphlet #20, pages 3-4. (Clark Collection: CWC 76-48A).
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.321207
label: accession number
content: 241556
label: catalog number
content: 321207
objectType: label: Object Name
content: radio component
physicalDescription: label: Measurements
content: overall: 8 1/2 in x 8 in x 4 1/2 in; 21.59 cm x 20.32 cm x 11.43 cm