Question

The Z parameters $Z_{11}$ and $Z_{21}$ for the 2-port network in the figure are

• A. $Z_{11}=\frac{-6}{11}\Omega ;Z_{21}=\frac{16}{11}\Omega$
• B. $Z_{11}=\frac{6}{11}\Omega ;Z_{21}=\frac{4}{11}\Omega$
• C. $Z_{11}=\frac{6}{11}\Omega ;Z_{21}=\frac{-16}{11}\Omega$
• D. $Z_{11}=\frac{4}{11}\Omega ;Z_{21}=\frac{4}{11}\Omega$

Answer 1

The correct option is C $Z_{11}=\frac{6}{11}\Omega ;Z_{21}=\frac{-16}{11}\Omega$

$V_1=Z_{11}{I}_1+Z_{12}{I}_2$

$V_2=Z_{21}{I}_1+Z_{22}{I}_2$

$Z_{11}={\begin{array}{c}\frac{V_2}{I_1}\end{array}|}_{I_2=0}$

KVL in RHS loop,

$E_2-4I_1+10E_1=0$

$\Rightarrow E_2-4I_1+10x\frac{6}{11}{I}_1=0(E_1=\frac{b}{11}{I}_1)$

$\Rightarrow 11E_2-44I_1+60I_1=0$

$\Rightarrow \frac{E_2}{I_1}=-\frac{16}{11}\Omega$