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oscilloscope os·cil·lo·scope (ə-sĭl'ə-skōp')
An electronic instrument that produces an instantaneous trace on the screen that corresponds to oscillations of voltage and current.
An electronic instrument used to observe and measure changing electrical signals. The amplitude of the signal as it varies with time is displayed graphically on a screen as a line stretching from left to right, with displacements up and down indicating the amplitude of the signal. Oscilloscopes are used to diagnose problems in electronic signal-processing devises, such as computers or stereos, and to monitor electrical activity in the body, such as that of heartbeats.