Question

A transistor is used as an amplifier in CB mode with a load resistance of 5 kW the current gain of amplifier is 0.98 and the input resistance is 70 W, the voltage gain and power gain respectively are –

• A. 70, 68.6
• B. 80, 75.6
• C. 60, 66.6
• D. 90, 96.6

Answer 1

Answer: (A)

70, 68.6

Answer 2

a = $\frac{I_{C}}{I_{E}}$= 0.98

V_a = a $\frac{R_{L}}{R_{in}}$= 0.98 × $\frac{5 \times 10^{3}}{70}$

P_a = a² $\frac{R_{L}}{R_{in}}$ = (0.98)² × $\frac{5 \times 10^{3}}{70}$