Hand-drawn oscillograms Oscilloscope history

illustration of joubert s step-by-step method of hand-plotting waveform measurements.

the earliest method of creating image of waveform through laborious , painstaking process of measuring voltage or current of spinning rotor @ specific points around axis of rotor, , noting measurements taken galvanometer. advancing around rotor, general standing wave can drawn on graphing paper recording degrees of rotation , meter strength @ each position.

this process first partially automated jules françois joubert step-by-step method of wave form measurement. consisted of special single-contact commutator attached shaft of spinning rotor. contact point moved around rotor following precise degree indicator scale , output appearing on galvanometer, hand-graphed technician. process produce rough waveform approximation since formed on period of several thousand wave cycles, first step in science of waveform imaging.