National Radio Tube type R-3 "Rectobulb"
date: label: date made
content: ca 1930
name: label: maker
content: National Radio Tube Company
notes: label: Description (Brief)
content: National Radio Tube type R-3 Rectobulb in original box. Marked: "National Radio / Tube Co.", stamped: National / R3 / Rectobulb." A double-ended rectifier tube with a 4-pin base including filament connections on one end, and a plate lead on top. Box reads in part: "National / Rectobulb / Type R-3 / Fil. Volts .... 10 / Fil. Amps .. 1.75 / Plate volts . 110 to 3000 / Plate Amps.. (.25) / Important / Allow the Cathode about 30 / seconds for heating before / applying the plate voltage / and keep filament lit. / National / Radio Tube / Company / 3420 18th Street / San Francisco, Calif." Handwritten on box: "R-3 / Rectobulb / Used / & How". Reference: Tyne, "Saga of the Vacuum Tube," page 359; and https://www.radiomuseum.org/tubes/tube_r3_rectobulb.html.
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.RSN80522U00
objectType: label: Object Name
content: rectifier
label: Other Terms
content: Electron Tube; Electron Tubes
physicalDescription: label: Physical Description
content: cardboard (box material)
label: Physical Description
content: composition (overall material)
label: Physical Description
content: glass (overall material)
label: Physical Description
content: metal (overall material)
label: Measurements
content: tube: 8 1/2 in x 3 in; 21.59 cm x 7.62 cm
label: Measurements
content: box: 9 in x 3 1/4 in x 3 1/4 in; 22.86 cm x 8.255 cm x 8.255 cm