A new portable oscillograph

A knowledge of the wave forms of voltages and currents is often of great value to experimental work or in the analysis of the characteristics of electrical circuits and apparatus. This paper describes a portable oscillograph whereby the wave shapes and phase relations of voltages and currents can be observed and photographed almost as easily as their effective values can be measured with the ordinary portable instruments. Because of its simplicity of operation, and because the wave shapes can be observed simultaneously by a large group of persons the instrument is of particular value to scientific and engineering schools.