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Question
When the base current in a transistor is changed from 30µA to 80µA, the collector current is changed from 1.0 mA to 3.5 mA. Find the current gain β.
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Solution
Given:
Change in the base current, \[\delta I_b = (80 - 30) \mu \text{A}\]
Change in the collector current, \[\delta I_c = (3 . 5 - 1) \] mA
Thus,
\[\beta = \left( \frac{\delta l_c}{\delta l_b} \right) \text{at constant V}_{cc} \]
\[ \Rightarrow \beta = \frac{2 . 5 \times {10}^{- 3}}{50 \times {10}^{- 6}}\]
\[ \Rightarrow \beta = \frac{250}{50} = 50\]
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