Catalogue
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Marconi Radio Valve Type DEQ, by Marconi Company, England, c. 1923
Inventory Number: 20655
Date: c. 1923
Maker Details: Signed by Marconi-Osram Valves.
Inscription: "THE M.O. VALVES CO. LTD / MADE IN ENGLAND / R.A.F./ R3B [AIR MINISTRY LOGO] / 307 ____ A.M." printed on exterior surface of bulb.
Size: 70 mm in overall length
Materials: Glass, steel, assorted metals.
Other Given Number(s): Christie's 210.
Notes:
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. This particular example was clearly made for the Royal Air Force as demonstrated by the R.A.F. and Air Ministry stamps on the exterior surface. Previously catalogued with assorted other valves.
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