Cool oscillator waveforms come to life
An oscilloscope (commonly abbreviated to scope or O-scope) is a type of electronic test equipment that allows signal voltages to be viewed, usually as a two-dimensional graph of one or more electrical potential differences (vertical axis) plotted as a function of time or of some other voltage (horizontal axis). The oscilloscope is one of the most versatile and widely-used electronic instruments. 
Oscilloscopes are widely used when it is desired to observe the exact wave shape of an electrical signal. In addition to the amplitude of the signal, an oscilloscope can measure the frequency, show distortion, and show the relative timing of two related signals. Oscilloscopes are used in the sciences, medicine, engineering, telecommunications, and industry. General-purpose instruments are used for maintenance of electronic equipment and laboratory work. Special-purpose oscilloscopes may be used for such purposes as adjusting an automotive ignition system, or to display the waveform of the heartbeat.
Originally all oscilloscopes used cathode ray tubes as their display element, but modern digital oscilloscopes use high-speed analog-to-digital converters and computer-like display screens and processing of signals. Oscilloscope peripheral modules for general purpose laptop or desktop personal computers can turn them into useful and flexible test instruments.