Western Electric type 212D transmitting triode
date: label: date made
content: ca 1928
name: label: maker
content: Western Electric
notes: label: Description (Brief)
content: A 250 watt transmitting triode with 4-pin metal base, red fiber insulator, tipped T-shaped envelope. Marked: "Western Electric / Made in U.S.A. / 212 D / Patent / 1209324 RE-14572 1303579 1307510 1329283 1353976 1419528 1435867 1456528 1463850 1454101 1478072 1479991 1491362 1536855 1542366 1542385 1590352 1505230 1513630 1547994 1573008 / Pat. Pend." Also, "3". Donor’s card reads: “Triode made by the Western Electric Company for use as modulators and oscillators in their first commercial 500 watt broadcast equipment. Used two in parallel for both oscillators and modulators in the Colpitts-Heising circuit. Used in 50% of all broadcasting between 1924 and 1933 when higher power and other makes of equipment became available. Completely unsuited for any frequency above 1500 kilocycles. Mounted on a base which was used on no other tube at that time. Never made available for amateur use and would have been of little use if [available] as the base insulation disc frequently broke down between pins from parasitic frequencies in broadcasting. Thoriated tungsten filament: 14 volts at 6 amperes. As a Class C amplifier, 1500 volts on the plate at 300 milliamps, 200 volt negative grid bias, this tube would give a carrier of about 300 watts per tube. The type 212 series was developed after WW1 and were known as type I tubes. The 212-D model was introduced in 1924 and the E model somewhat later. See also: https://www.westernelectric.com/s/212D.pdf.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from Paul G. Watson
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.324551
label: catalog number
content: 324551
label: accession number
content: 252994
objectType: label: Object Name
content: Electron Tube, Triode
label: Object Name
content: triode
label: Other Terms
content: Electron Tube, Triode; Electron Tubes
physicalDescription: label: Measurements
content: overall: 13 in x 3 1/2 in; 33.02 cm x 8.89 cm