Catalogue
275 of 655 records previous / next
Marconi-Osram Radio Valve Type DER, by Marconi Company, London, c. 1923
Inventory Number: 48922
Number of documents: 3
Document Type: Miscellaneous Note
Document Heading: Inscription - Inv. Num. 48922
Text:
"BBC [LOGO] / D.E.R. / 16942" 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 lower exterior surface of bulb.
Document Type: Miscellaneous Note
Document Heading: Technical Details - Marconi Radio Valve Type DER
Text:
The DER valve was an adaptation of the LT1 valve, the first British dull emitter valve. The LT1 was produced in 1921 but went through minor modifications and was re-issued as the DER valve in 1922. Initial versions of the DER valve had construction similar to that of the LT1 but soon a new version was produced with a tapered tubular bulb and a B4-3 metal-shell base. This in turn was replaced by a version with a horizontally mounted electrode assembly, similar to that of the Type R valve. Later versions removed the top seal and had a B4/m moulded bakelite base. The Type DER valve were eventually replaced by the DEV valve.
Document Type: Miscellaneous Note
Document Heading: Manufacturer Details
Text:
Marconi-Osram Valve Co. Ltd. was founded in 1919, and took over the manufacture of Marconi valves from Ediswan, the trade name of the Edison and Swan United Electric Light Company Limited. The M-OV, as it was later known, was a joint Marconi-GEC valve-manufacturing company. It produced all of its valves at the Osram Lamp Works at Hammersmith, London.
275 of 655 records previous / next
Record mode: Basic | Medium Images | Large Images | Documents (3)