Development of A UHF Grounded-Grid Amplifier

The 6AJ4 is a nine-pin miniature, grounded-grid triode designed to operate as the radio-frequency amplifier in uhf television receivers. This paper reviews the development of this tube, treats the special problems encountered in extending the useful frequency range of a miniature tube to beyond 890 mc, and discusses the methods employed in arriving at a useful solution. Special attention is given the problem of isolation between input and output circuits. The techniques of the measurements involved in the development of this tube are also discussed.