Abbreviation for Cathode Ray Oscilloscope. A very handy analysis tool for examining wave outputs, finding dead connections, and seeing your voice. The basic workings of the oscilloscope are as follows: The main component is a cathode ray tube. An electron gun fires a beam of electrons onto a phosphorescent screen, producing a little dot. The X deflectors move the dot from left to right across the screen, fast enough to create a continuous line. The Y deflectors are connected to the input probes of the oscilloscope. This causes the dot to move up and down, creating a waveform consistent with the input signal.