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.