An oscilloscope is an electronic instrument that is used to indicate voltage of an electronic device. It is chiefly used to diagnose the working condition of any electric equipment. It represents one or more electric potential differences in a two-dimensional graph, with the horizontal axis representing time and the vertical axis showing voltage. Some oscilloscopes can show even two or more waveforms. These are used for phase comparison and timing measurements.

An oscilloscope can be used to find out exactly which part of the electrical equipment is faulty. The oscilloscope's ground is put on the circuit's ground and its probe is put on a connection between any two stages in the middle of an array of stages. If there is no signal, it indicates that some part in the preceding stage is not functioning properly. This will enable us to locate exactly which component is not working. This is very useful since electronic equipments stop functioning because of just one faulty component within the whole equipment. Another application of an oscilloscope is to test newly designed circuitry. Software engineers also used oscilloscopes for testing the electronics of software.

An oscilloscope is shaped like a rectangular box. It has a small screen, several control knobs, input connectors and buttons on the front panel. The screen has a grid drawn over it, known as the graticule. Each grid in the graticule is called a division. The oscilloscope keeps drawing a horizontal line across the middle of the screen. This line, or the trace, keeps moving from left to right over the screen. If the input voltage deviates from zero, the trace deflects upwards or downwards. There are two controls which monitor this deflection: timebase control, which monitors the speed of the line in seconds per division; and the vertical control, which monitors the vertical deviation in volts per division. It thus gives a graph of voltage/time.

There are different kinds of oscilloscopes: analog oscilloscope, digital oscilloscope, digital storage oscilloscope, digital phosphor oscilloscope and digital sampling oscilloscope. Agilent, B+K Precision, EZ Digital, Extech Instruments Corp., Fluke, Instek, International Tools & Technologies, Inc., Iwatsu, Kenwood TMI Corp., LeCroy, Morrow Wave, Tektronix and Yokogawa are some of the popular oscilloscope manufacturers.

Information about oscilloscopes, along with their prices and product facts can be sourced from the internet. There are hundreds of websites that give information about oscilloscopes.