An oscilloscope is a measuring instrument used to observe electrical signals supplied to input sockets on a screen in the form of so-called waveforms. These instruments dynamically plot time-varying electrical signals in Cartesian coordinates. On the oscilloscope's "Y" (vertical) axis, voltage is plotted, while on the "X" (horizontal) axis, time is shown. The resulting graph of voltage as a function of time shows the image of the input signal and is usually referred to, as mentioned above, as a "waveform".

The oscilloscope is one of the most important measuring instruments used by electronics engineers in laboratories to test and verify designed devices. In electronic equipment service centers, they are an essential tool for locating damaged components. At universities and secondary technical schools, they allow phenomena to be visualized, making them easier for students to understand.