Question

In a common emitter amplifier, the collector resistance is 3 times the base resistance. If the common emitter current amplification factor is 60, then the power gain of the amplifier is:

• A. 21600
• B. 10800
• C. 3600
• D. 5400

Hint:

Power gain = Voltage gain × Current gain.
Voltage gain = $\beta \cdot R_C / R_B$.
Check units of resistances carefully.
Collector>base resistance → amplification increases.

Answer 1

The Correct Option is A

• Voltage gain: $A_v = I_c R_C / I_b R_B = \beta \cdot (R_C / R_B)$, where $\beta = 60$, $R_C / R_B = 3$.
• $A_v = 60 \cdot 3 = 180$.
• Power gain $G = A_v \cdot A_i$, but $A_i \approx \beta = 60$.
• $G = 180 \cdot 60 = 10800$? Wait options: collector resistance 3× base → $A_v = R_C/R_B \cdot \beta = 3 * 60 =180$, $G = A_v * \beta = 180*60=10800$. Actually correct: 10800.