___________________________________________________ Principles of Transmission Lines
Figure 3-24. Reflection from an Open-Ended Line
3-92. At this point, the same process takes place with the next to the last
inductor and capacitor. When the magnetic field about the inductor collapses,
current continues to flow into the next to the last capacitor, charging it to E
volts. This action continues backward down the line until the first capacitor
has been fully charged to the applied voltage. This change of voltage, moving
backward down the line, can be thought of in the following manner. The
voltage, arriving at the end of the line, finds no place to go and returns to the
sending end with the same polarity (figure 3-24, view C). Such action is called
reflection.
3-93. When a reflection of voltage occurs on an open-ended line, the polarity
is unchanged. The voltage change moves back to the source, charging each
capacitor in turn until the first capacitor is charged to the source voltage and
the action stops (figure 3-24, view D). As each capacitor is charged, current in
each inductor drops to zero, effectively reflecting the current with the
opposite polarity (view C). Reflected current of opposite polarity cancels the
original current at each point, and the current drops to zero at that point.
3-29
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