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History of Science Museum

Marconi Radio Valve Type DEQ, by Marconi Company, English, c. 1923

Inventory Number 29390


Acknowledgement: © History of Science Museum, University of Oxford, inv.29390

Item type
Object
Provenance
Presented by the Marconi Corporation.
Primary inscriptions
"D.E.Q. MARCONI / VALVE / B / PATENTED / MADE IN ENGLAND / PRODUCED FOR M.I.M.C.CO.LTD. / 204" printed on exterior surface of bulb.
Object type
Radio valve
Dimensions
Diameter: 27mm Height: 75mm Weight: 0.05kg
Inventory No
29390
Accession Number
2004-9/340

Description

Marconi Radio Valve Type DEQ (Dull Emitter Q), in thin glass envelope. With single wire filament running the length of the envelope and tensioned by a spring at end opposite the anode and grid brass supports. The anode and grid connections are on the envelope and pass to a shaped piece of glass rod that supports the electrodes. The grid helix can be clearly seen within envelope. A distinctive feature of DEQ valve is green band of paint around centre of envelope. Type DEQ valves had a very high impedance and primary function was as detector.