Oscilloscope, Oscilloscope Basics, How Oscilloscope works, Oscilloscope Definition, What is Oscilloscope

Electronic instrument for viewing and measuring electrical and electronic signals.
An instrument in which the variations in a fluctuating electrical signal appear as a visible wave on the fluorescent screen of a cathode ray tube an instrument for displaying electrical waveforms on a cathode ray tube
An oscilloscope (sometimes abbreviated CRO, for cathode-ray oscilloscope, or commonly just scope or O-scope) is a piece of electronic test equipment that allows signal voltages to be viewed, usually as a two-dimensional graph of one or more electrical potential differences

An instrument used to display a signal graphically. Shows signal amplitude, period and waveshape in addition to any DC voltage present. A multiple trace oscilloscope can show two or more waveforms at the same time for phase comparison and timing measurements

A device that displays the wave form created by an electrical generating device such as a generator, inverter, or utility

The oscilloscope is the most powerful instrument in our arsenal of electronic instruments.  It is widely used for measurement of time-varying signals.  Any time you have a signal that varies with time - slowly or quickly - you can use an oscilloscope to measure it - to look at it, and to find any unexpected features in it.

       In a real oscilloscope, the trigger signal can be generated when the signal value reaches some particular level called the trigger level.  In most cases you can set the trigger level to a voltage value of your choosing.