- Item type
- Object
- Provenance
- Presented by the Marconi Corporation.
- Primary inscriptions
- "MARCONI OSRAM VALVE / MADE AT THE OSRAM LAMP WORKS / COVERED BY VARIOUS PATENTS" printed on exterior surface of bulb. "BBC [LOGO] / D.E.R. / _7577" printed on exterior surface of bulb. "Fil. Volts 1.8-2.0 Fil. Amps 0.4 av. Anode Volts 30-50 / This Valve has been thoroughly tested before leaving the / Works, and no responsibility can be accepted for Valves / used under conditions other than the above." printed on label attached to upper section of exterior surface of base.
- Object type
- Radio valve
- Dimensions
- Diameter: 45mm Height: 115mm Weight: 0.05kg
- Inventory No
- 43964
- Accession Number
- 2004-9/356
Description
Marconi Dull Emitter Radio Valve (or Tube) Type DER (Dull Emitter R) with mostly silvered glass balloon envelope, nickel-plated plastic? base and four brass? base pins. The construction was of a cylindrical anode with a helical grid passing through it, threaded by a filament. Previously catalogued with two other, similar Type DER Radio Valves (Inv. Num.s 15591, 80189).
Related Items
More related items- Marconi Radio Valve Type DER, by Marconi Company, London, c.1925Inventory Number 94119
Marconi Radio Valve Type DER, by Marconi Company, London, c. 1925Inventory Number 15591
Marconi-Osram Radio Valve Type DER, by Marconi Company, London, c. 1923Inventory Number 48922
Marconi-Osram Radio Valve Type DER, by Marconi Company, London, 1920sInventory Number 80189