Use of an Oscillograph for Recording Vacuum-Tube Characteristics

This paper describes the method involved and results obtained in using an oscillograph for plotting photographically vacuum-tube characteristics. The main requirement is an alternating voltage of fairly pure wave-form with as few harmonics as possible. The "dynatron" action of vacuum tubes is shown very clearly when large alternating e.m.f.'s are applied to the grid. Static and dynamic characteristics can also be quite easily recorded.