Northern Electric type R221D vacuum tube
date: label: date made
content: ca 1927
name: label: maker
content: Northern Electric Manufacturing Company
notes: label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: ZZ.RSN80564U05
objectType: label: Object Name
content: Electron Tube, Triode
label: Object Name
content: triode
label: Other Terms
content: Electron Tube, Triode; Electron Tubes
physicalDescription: label: Physical Description
content: composition (overall material)
label: Physical Description
content: glass (overall material)
label: Physical Description
content: metal (overall material)
label: Measurements
content: electron tube, triode: 10 cm x 3.5 cm; 3 15/16 in x 1 3/8 in
label: Measurements
content: overall: 4 in x 1 1/2 in; 10.16 cm x 3.81 cm