An oscilloscope is an electronic display instrument for the graphic representation of electrical signals that can vary over time. It is widely used in signal electronics, often with a spectrum analyzer.

It presents the values of the electrical signals in the form of coordinates on a screen, in which the x-axis (horizontal) normally represents times and the y-axis (vertical) represents voltages. The image thus obtained is called an oscillogram. They usually include another input, called "THRASHER axis" or "Wehnelt cylinder" that controls the brightness of the beam, allowing some segments of the trace to be highlighted or turned off.

The oscilloscopes, classified according to its internal functioning, can be both analogue and digital, the result being identical in either case, at least in theory.

In an oscilloscope there are basically two types of controls that are used as regulators that adjust the input signal and allow measurement on the screen and, in this way, one can see the shape of the signal measured by the oscilloscope. In a technical way, it can be said that the oscilloscope is used to observe the signal to be measured.

More Info: en.wikipedia.org