Figure 2.25. This is a simplified drawing of a cathode ray tube. The outline of the tube starts on the left and is tubular for about 1 third of the length. Then it starts to widen out like a slender funnel on its side. At the right end it has become a little more than twice as wide as it is at the left end. Just inside the left end of the outline is a shallow V on its side with the point to the right. Two lines connect to the left ends of the V and cross to end outside the outline. This V is labeled heater. The lines crossing the outline indicate there are electrical connections to the heater on the outside of the tube. Usually, but not always, through pins on the small end of the tube. To the right of the heater is a vertical line as long as the heater. There are short lines which go to the left on each end of the vertical line. Connected to the lower short horizontal line is a line which crosses the outline to the outside. This part is labeled cathode. To the right of the cathode is a rectangle which is vertically the same height as the cathode and horizontally extends nearly to the point where the outline of the tube begins to widen out. There are three lines from this rectangle coming down and crossing the tube outline to the outside. This rectangle is labeled accelerating electrode assembly. In the real tube this assembly is cylindrical as is the tube. To the right of the accelerating assembly are two vertical deflection plates. They are square plates which are horizontal and placed one at the top and one at the bottom of the tube. Each plate is connected to the outside of the tube. To the right of the vertical deflection plates are the horizontal deflection plates. They are similar to the vertical plates except they are vertical and are placed one closest to the viewer and the other behind it as we see it farther from the viewer. The electron beam passes between these sets of plates and can be bent up or down by the first set and left or right by the second set. The right end of the tube has its inside coated with a substance which emits visible light when electrons impact on it. This is labeled the screen. End verbal description.
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