1. An oscillograph that records signal waveforms by means of a moving-coil galvanometer or it is also known as a device for recording the wave-forms of changing currents, voltages, or any other quantity that can be translated into electric energy; such as, sound waves.
2. An oscillograph in which the recording mechanism is controlled by a moving-coil galvanometer; such as, a direct-writing recorder or a light-beam oscillograph (device for making a record of the wave forms of fluctuating voltages or currents).