- Item type
- Object
- Provenance
- Presented by the Marconi Corporation.
- Primary inscriptions
- "MARCONI / VALVE / PATENTED / MADE IN ENGLAND" printed on exterior surface of bulb. "BBC [LOGO] / D.E.R. / FIL. 1.8 VOLTS / 1462A" printed on exterior surface of bulb.
- Object type
- Radio valve
- Dimensions
- Diameter: 45mm Height: 100mm Weight: 0.05kg
- Inventory No
- 15591
- Accession Number
- 2004-9/334
Description
Marconi Radio Valve (or Tube) Type DER (Dull Emitter R) with partially silvered glass balloon envelope, polished black bakelite base and four steel base pins. The construction was of a cylindrical anode with a helical grid passing through it, threaded by a filament. BBC logo ("ENTIRELY BRITISH MANUFACTURE") was used between September 1924 and 1927 and is a good indication of date of origin. Previously catalogued with two other, similar Type DER Radio Valves (Inv. Num.s 43964, 80189).
Related Items
More related items- Marconi Radio Valve Type DER, by Marconi Company, London, c.1925Inventory Number 94119
Marconi-Osram Radio Valve Type DER, by Marconi Company, London, c. 1923Inventory Number 48922
Marconi-Osram Radio Valve Type DER, by Marconi Company, London, c. 1923Inventory Number 43964
Marconi-Osram Radio Valve Type DER, by Marconi Company, London, 1920sInventory Number 80189