BCECE Engineering BCECE Engineering Solved Paper-2001

  • question_answer
    State which of the following is correct?

    A) \[{{g}_{m}}=\mu \times {{r}_{p}}\]

    B)        \[{{r}_{p}}=\mu \times {{g}_{r}}\]

    C)         \[\mu ={{r}_{p}}\times {{g}_{m}}\]

    D)         \[\mu =\frac{{{r}_{p}}}{{{g}_{m}}}\]

    Correct Answer: C

    Solution :

    \[\mu ,{{r}_{p}}\]and \[{{g}_{m}}\]are three constants of a triode valve, namely amplification factor, internal  resistance    and    mutual    conductance respectively. \[\mu =\left( \frac{\Delta {{V}_{p}}}{\Delta {{V}_{g}}} \right)\] (for same amount of increase in\[{{i}_{p}}\]) \[{{r}_{p}}=\left( \frac{\Delta {{V}_{p}}}{\Delta {{i}_{p}}} \right)\] (while\[{{V}_{g}}\]is constant) and \[{{g}_{m}}=\left( \frac{\Delta {{i}_{p}}}{\Delta {{V}_{g}}} \right)\](while \[{{V}_{p}}\]is constant) We have, \[\mu =\frac{\Delta {{V}_{p}}}{\Delta {{V}_{g}}}=\frac{\Delta {{V}_{p}}}{\Delta {{i}_{p}}}\times \frac{\Delta {{i}_{p}}}{\Delta {{V}_{g}}}={{r}_{p}}\times {{g}_{m}}\] \[\mu ={{r}_{p}}\times {{g}_{m}}\]


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