current, and impedance variations along a short-circuited, half-wave
section. The impedance at the short circuit is minimum because the voltage,
current, and impedance variations along a short-circuited, half-wave
section. The impedance at the short circuit is minimum because the voltage
is minimum and the current maximum. These same conditions are repeated at
the generator. At the generator, the impedance is minimum also. The half-
wave section appears to the generator as a series-tuned circuit.
Figure 21. Voltage, Current and Impedance Variations
on a Half-Wave Section of Transmission Line.
b. The open-circuited, half-wave section has the characteristics of a
parallel-tuned circuit.
Part B of Figure 21 shows that the voltage is
maximum and the current minimum at the open end. These conditions result in
a high impedance at that point. One-half wavelength back at the generator,
these conditions are repeated. The generator appears to be working into a
parallel-tuned circuit with the characteristics of high voltage, low
current, and high impedance.
32. Summary of the half-wave line.
a. The short-circuited, half-wave section acts
as
a
series-tuned
circuit. It presents a low impedance to the source.
b. The open-circuited, half-wave section acts like a parallel-tuned
circuit. It presents a high impedance to the source.
c. The half-wave line repeats the load. A low resistive load appears
as a low resistance to the generator.
A high resistance at the load end
appears as a high resistance to the generator.
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