For the network of Fig. 5.151, calculate the DC operating point and the small-signal voltage gain.

Here are the solutions for Problems 11 and 12 from the image you sent.

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: For the network of Fig. 5.151:
Given: $V_{CC} = 12 \, \text{V}$, $R_B = 220 \, \text{k}\Omega$, $R_C = 2.2 \, \text{k}\Omega$, $\beta = 60$.
Assume $V_{BE} = 0.7 \, \text{V}$ for a silicon transistor.

First, calculate the DC operating point to find $r_e$.

Step 1: Calculate the base current $I_B