Figure 4.25. There are two terminals on the left labeled G, upper and S, lower. On the right are two more terminals labeled D, upper and S, lower. The G terminal connects to nothing indicating it is a voltage sensitive point. There is a current source labeled G sub m V sub gs. The arrow in the current source is pointing downward. The lower end of the current source is connected to the bottom line of the circuit. Both S terminals are also connected to the bottom line. The top of the current source is connected to the D terminal. There is a resistor labeled r sub d connected between the D and S terminals. The r in r sub d is a lower case r. Real resistors are labeled with an upper case R. End verbal description.