Abstract :
A theory of the common-grid earthed-grid amplifier, commonly called the grounded-grid amplifier, for medium transit angles is presented, showing the advantages this valve possesses over the earthed-cathode amplifier. A description of a range of valves using disc seals is given and their performance indicated, mention being made of the circuit advantages offered by the use of disc seals in valves. The results obtained on experimental valves are presented, and for signal/noise ratio improvement the probable upper limit of 2 000 Mc/s with present techniques is suggested, 5 000 Mc/s being the probable limit for oscillators. The two important problems awaiting theoretical attack are ¿total-emission damping¿ and high-frequency slope.
