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VMMC VMMC Medical Solved Paper-2007

  • question_answer
    A transistor is operated in common emitter configuration at constant collector voltage \[{{V}_{C}}=1.5\,V\] such that a change in the base current from 100\[\mu A\] to 150\[\mu A\] produces a change in the collector current from 5 mA to 10 mA. The current gain (\[\beta \]) is

    A) 67          

    B)                        75                          

    C) 100                        

    D)        50

    Correct Answer: C

    Solution :

    AC current gain \[\beta \] is defined as the ratio of the collector to the base current at constant collector voltage, \[\beta =\left( \frac{\Delta {{i}_{C}}}{\Delta {{i}_{B}}} \right){{V}_{c}}\] Given \[\Delta {{i}_{C}}=10\,mA-5mA=5mA\]                 \[\Delta {{i}_{B}}=150\,\mu A-100\mu A=50\,\mu A\] \[\therefore \]  \[\beta =\frac{5}{50\times {{10}^{-3}}}=100\]


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