3-19
Figure 3-18.—Dc voltage applied to a line.
Ac Applied to a Transmission Line
When the battery of figure 3-18 is replaced by an ac generator (fig. 3-19), each successive
instantaneous value of the generator voltage is propagated down the line at the speed of light. The action
is similar to the wave created by the battery except that the applied voltage is sinusoidal instead of
constant. Assume that the switch is closed at the moment the generator voltage is passing through zero
and that the next half cycle makes point A positive. At the end of one cycle of generator voltage, the
current and voltage distribution will be as shown in figure 3-19.
