Figure 4.17. In this diagram the FET is upright with the source at the bottom and the drain at the top. The gate is on the left. The rectangle has been widened to better show the depletion region. The outer rectangle is almost as wide as it is high. The smaller rectangle, representing the gate, is on the left and centered top to bottom. There are 3 circles, holes, in the gate region clustered near the connection. 2 are below the connection and the remaining one is above it. In the larger, outer, rectangle the electrons are some distance from the boundary, junction, at the bottom but get farther away from it as height increases. At the top the electrons are quite far away from the junction. There is a battery on the left with its positive end connected to the source and its negative connected to the gate. There is another battery on the right with its negative end connected to the source and its positive end connected to the drain. End verbal description.