Figure 4.1. There is a common connection line running from left to right across the bottom of the diagram. In the center, and slightly above the line is a rectangle which is about 4 times as wide as it is high. This rectangle is labeled emitter. Above the emitter rectangle and touching it is another which is as wide but about half as high. This one is labeled base. Above the base rectangle, and touching it, is another which is the same width and height as the emitter one. It is labeled collector. The emitter rectangle is connected to the common line. On the left is a battery labeled V sub BB. Its negative end is connected to the common line. The positive end goes through a resistor labeled R sub B, value not given, to the base rectangle. On the right is another battery labeled V sub CC. Its negative end goes to the common line. The positive end goes through another resistor labeled V sub C, value not given, to the collector rectangle. End verbal description.