E. H. ARMSTRONG

Evening Post, Volume CVII, Issue 61, 15 March 1924, Page 22

E. H. ARMSTRONG

Professor Edwin H. Armstrong, of tlie Columbia University, TJ.S.A., is undoubtedly the most brilliant .of the younger group of wireless scientists. Born in 1890, he is still in the early thirties and has admittedly been responsible for more far-reaching developments" in wireless practice than any other man of his age. As early as 1912 he commenced a series of investigations into the three-electrode valve, which culminated in the discovery of the principle of regeneration or reaction. Curiously' enough, the effect of back-coup-ling the grid tfnd plate circuits of a valve was also discovered about the same time, and apparently along independent lines, by Franklin, in England, and by the Graf yon Arco and Meissner in Germany. So far as records are available, however, Armstrong appears to have been in possession of a regenerative circuit in: January of 1913. three months before the date of the first German invention and six months prior to the date of Franklin's British.platent. • During the war Armstrong gained further laurels by designing a super-hetero-dyne receiver of extraordinary sensitivity. _ This found an immediate application in detecting signals sent by the low-powered short-wave trench sets employed by the Germans in combination with small loop aerials for transmitting confidential messages to and from the front lines.

His final discovery of the new principle of amplification which is embodied in the Armstrong "super" dates from June, 1921, although it was not announced to the public generally until a year later. The results obtained by what the inventor has termed the state of "super-regeneration" probably represents the utmost limit to which valve amplification can be pushed.* At'the same time it is unsafe to set any bounds to the possibilities of the thermionic valve, which has- an unpleasant habit of suddenly developing new qualities and upsetting previous calculations.—H.