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oscillograph os·cil·lo·graph (ə-sĭl'ə-grāf')
A device that records oscillations, as of an electric current and voltage.
instrument for indicating and recording time-varying electrical quantities, such as current and voltage. The two basic forms of the instrument in common use are the electromagnetic oscillograph and the cathode-ray oscillograph; the latter is also known as a cathode-ray oscilloscope (q.v.), which, strictly speaking, is purely an indicating instrument, while the oscillograph can make permanent records.