Laboratory Jottings

Radio Record, Volume IV, Issue 19, 21 November 1930, Page 8

Laboratory Jottings

Fi Diamond Valves p os FROM Messrs.:Royds, Howard, Ltd., Christchurch, .we have received samples of Diamond valves for test. These are a good line and equalling the standard in very many respects. Both filament and plate are constructed to withstand overloads, and although we imposed severe strains on them there were no flash overs. This applies to the 280 full wave -rectifying valve as well as to the others. Mechanically, construction of the valves appears to be ‘quite rigid, and although they were submitted to rough handling, flaws did not show up. ‘The internal resistance of these valves is identical with that of the standard valves of the same types. Those submitted us for test were: 224, 245, 280, 227, and 201A. The prices are 226 13/-, 227 18/-, 280 16/6, 245 17/6, 224 27/-. These can be used quite well in any set taking this type of valve, and there is little doubt that, as far as many combinations are concerned they will be a distinct advantage. Another Diamond product sent along for test was 44 volt "C" battery. There is no skimping in this battery. The cells are large and consequently last for a considerable time. The container was well constructed and the finish good, and if this is a sample of the line of Diamond batteries, they can be recommended. Clips are used to attach leads, and not screw terminals, as is usually the case, db