AN UNHAPPY READER--"Sirs, the article in August 1951, by Louis N. Ridenour, properly entitled 'A Revolution in Electronics,' is most interesting. The article, however, conveys an entirely erroneous impression: that the three-electrode tube amplifier has virtually come to the end of its career. Dr. Ridenour neglected to mention the frequency limitations of the transistor. Under such limitations, it cannot begin to compete with the three-electrode tube, or audion, as I first styled it. The general application of the transistor in radio and television receivers is far in the future. --Lee deForest"