Question

Voltage standing wave pattern in a lossless transmission line with characteristic impedance 50 $\Omega$ and a resistive load is shown in the figure.

The value of the load resistance is

• A. 200 $\Omega$
• B. 50 $\Omega$
• C. 12.5 $\Omega$
• D. 0 $\Omega$

Answer 1

The correct option is C 12.5 $\Omega$

Ans : (c)

S = $\frac{V_{max}}{V_{min}}=\frac{4}{1}=4$

$Z_{max}=Z_0\cdot S$

$Z_{min}=Z_0/S$

The diagram shows that minima is at load

$\therefore Z_L=Z_{min}=\frac{50}{4}=12.5\Omega$