Valves of the Future

Radio Record, Volume V, Issue 11, 25 September 1931, Page 31

Valves of the Future

JSSPIRED by the advent of the pentode valve, George Lewis, of the Arcturus Valve Company, at an engineers meeting, reviewed the effect of valve developments and what they have meant to radio in the home. "There is no question," says _ My. Lewis, "that the pentode is the valve

of the day. . The pentode, of course, ' has three grids, and is to the screen grid valve what the scren grid is to the three element type. "As a matter of fact, radio, history seems to be summed up in the addition of electrodes to the fundamental principles. of the two element valves of Fleming and Edison, known as diodes. Back in 1907 De Forest added a grid to the Fleming valve, and increased its utility a hundred ‘fold. This three element valve was termed a triode. About fifteen years later the second grid was added to this: modern Aladdin’s lamp, and we were able to work new wonders with the genii of radio.. The name, tetrode, was applied to this type. Now we add a third grid or fifth element and have the pentode. "With each element that has been added to a radio valve it has, inversely, made possible the reduction in ‘size of radio sets, The early sets were large, cumbersome affairs, while the present-day sets are less than half the size. of their predecessors, and thous-ands-fold more efficient. "What shall we look forward to in the way of further developments-a hexode, octode or even dekode?’