Question

For a transistor in common base, the current gain is 0.95. If the load resistance is $ 400\,k\Omega $ and input resistance is $ 200\,k\Omega , $ then the voltage gain and power gain will be

• A. 1900 and ,1800
• B. 1900 and 1805
• C. 5525 and 3591.
• D. 1805 and 1900

Answer 1

Answer: (B)

Given, $ \alpha =0.95,\,{{R}_{0}}=400\times {{10}^{3}}\,\Omega $
$ {{R}_{i}}=200\,\Omega $
As, voltage gain $ =\alpha \frac{{{R}_{0}}}{{{R}_{i}}} $
$ =0.95\times \frac{400\times {{10}^{3}}}{200} $
$ =1900 $
Power gain = Voltage gain $ \times $ Current gain
$ =1900\times 0.95 $ $ =1805 $