拍品 21
21
A rare type N 2V-PIF Round valve
No VAT will be charged on the hammer price, but VA… 显示更多
A rare type N 2V-PIF Round valve

细节
A rare type N 2V-PIF Round valve
No. N7789, MARCONI'S W. T. Co. Ltd, with extended pip containing asbestos powder for heat-controlled vacuum, globe lead-in shoulder for filament entry (no filament continuity), and large tubular plate, sidetaps with pitched edges, screw fitting base with green glass core insulator and circular paper label with testing mark for 18.11.20 above etched number, circa 1917 -6¾in. (7.1cm) long, (full original vacuum questionable - minor internal fungi growth present)
出版
Radio! Radio!, J. Hill, third edition, p.23;

70 Years of Radio Tubes and Valves, J. W. Stokes, Chp III, p. 11-12
注意事项
No VAT will be charged on the hammer price, but VAT at 15% will be added to the buyer's premium which is invoiced on a VAT inclusive basis.

拍品专文

Indentified by the letter prefix as to what the valve did; The letter 'N' shown on this example stood for Navy. Usually the more defined letters are seen as 'NR' for Naval Receiving, 'NT' for Naval Transmitting and 'NU' for Naval Rectifier.