The Cathode-ray Tube

The final thermionic device and active component to be described in this book is the cathode-ray tube, which is used as the display device in cathode-ray oscilloscopes and in television monitors and receivers. The types of tube that are used vary between the oscilloscope and television screen by virtue of the method of moving the electron beam across the screen. This chapter merely introduces the concept of the cathode-ray tube as a continuation of thermionic valve theory, the cathode-ray tube merely being a special adaptation of the triode valve with similar characteristics and parameters to those described in the previous chapter. Certain cathode-ray tubes have very different constructions and electron beam movements, such as those used for radar scanners, but although this was the application that introduced the cathode-ray tube into the world of electronics in 1936, the radar tube will not be described here.