An oscillograph was powered by the motor from a toy electric train.
From the latimes.com
The output of the amplifier drove a loudspeaker and an oscillograph.
From the newscientist.com
From the traces on their oscillograph, the biologists could tell whether an invisible bat was approaching or flying away.
From the time.com
Studying the fundamental processes of the oscillograph, Gabor was led to other electron-beam devices such as electron microscopes and TV tubes.
From the en.wikipedia.org
When the imitation bat sounded louder, as if it were closing in, the moth's ear responded more strongly, covering the face of the oscillograph with trains of wiggly warning lines.
From the time.com
The moving beam of light could also be used to make a record on a moving photographic film, producing a graph of current versus time, in a device called an oscillograph.
From the en.wikipedia.org
More examples
A device for making a record of the wave forms of fluctuating voltages or currents
An oscillograph is an instrument for measuring alternating or varying electric current in terms of current and voltage. There are two instruments that are in common use today: *Electromagnetic oscillograph *Cathode-ray oscilloscope
An instrument used to produce a record of the instantaneous values of one or more rapidly varying electrical quantities as a function of time. To analyze system troubles, automatic oscillographs at BPA substations provide a record of voltage and current variations on the transmission lines. ...