What is an Oscilloscope?
For those who work in education, design, service, maintenance, field service or quality control, an oscilloscope is the most important tool in meeting measurement challenges. Sometimes referred to as a scope, this instrument displays graphical representations of electrical signals. In most applications the graph shows how signals change over time; the vertical axis represents voltage and the horizontal represents time. The usefulness of an oscilloscope is not limited to the world of electronics. With the proper transducer, an oscilloscope can measure all kinds of phenomena. Due to the endless variations in performance and price, selecting the right oscilloscope is an important, yet daunting task.
A typical oscilloscope is a rectangular box with a small screen, numerous input connectors and control knobs and buttons on the front panel. To aid measurement, a grid called the graticule is drawn on the face of the screen. Each square in the graticule is known as a division. The signal to be measured is fed to one of the input connectors, which is usually a co-axial connector such as a BNC or N type. If the signal source has its own co-axial connector, then a simple co-axial cable is used; otherwise, a specialised cable called a scope probe, supplied with the oscilloscope, is used. In its simplest mode, the oscilloscope repeatedly draws a horizontal line called the trace across the middle of the screen from left to right. One of the controls, the timebase control, sets the speed at which the line is drawn, and is calibrated in seconds per division. If the input voltage departs from zero, the trace is deflected either upwards or downwards. Another control, the vertical control, sets t
