Western Electric 205D vacuum tube

Western Electric 205D vacuum tube

Usage conditions apply
Description (Brief)
Marked: "1701". In original box with instruction sheet. A moderate power triode designed for use as an audio frequency amplifier, but can also be used as an RF amplifier or oscillator. Eff = 4.5 volts; Ip = 1.6 amperes. Ep = 200 - 400 volts; Ip = 8 - 40 milliamps. Mu = 6.7 - 7.4; Rp = 3500 - 4800 ohms. Tyne notes that the locking pin on 205 type tubes was set 45o differently from other tubes to prevent low-power tubes from being inadvertently substituted. Reference: Tyne, "Saga of the Vacuum Tube," page 287.
"The No. 205D is a three-element filamentary type tube intended for use as a radio-frequency amplifier, oscillator, modulator, and audio-frequency amplifier in output stages when moderate powers are required." Reference: Western Electric 205D data sheet: https://www.westernelectric.com/s/205D.pdf.
Currently not on view
Object Name
Tube, Electron
vacuum tube
date made
ca 1925
Western Union Corporation
Western Electric
box: 5 3/4 in x 3 1/8 in x 3 1/8 in; 14.605 cm x 7.9375 cm x 7.9375 cm
triode: 4 1/4 in x 2 1/4 in; 10.795 cm x 5.715 cm
ID Number
accession number
catalog number
Credit Line
from Western Union Corporation
See more items in
Work and Industry: Electricity
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object