- Item type
- Object
- Provenance
- Presented by the Marconi Corporation.
- Primary inscriptions
- "MARCONI / VALVE / PATENTED / MADE IN ENGLAND / D.E.V. BBC [LOGO] / 366A" printed on exterior surface of bulb.
- Object type
- Radio valve
- Dimensions
- Diameter: 25mm Height: 75mm Weight: 0.05kg
- Inventory No
- 62884
- Accession Number
- 2004-9/324
Description
Marconi Radio Valve Type DEV (Dull Emitter V), with grid and anode connections as side pips on envelope, and single strand tungsten filament running entire length with spring for tensioning. BBC logo ('TYPE APPROVED BY THE POSTMASTER GENERAL') was used from 1st November 1922 until September 1924, and is a good indication of the date of origin. Previously catalogued with assorted other valves. Construction was co-axial with helical wire grid surrounding filament and fitting within cylindrical anode. In thin glass envelope half painted red, with envelope caps at either ends.
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