NEET Physics Semiconducting Devices NEET PYQ-Semiconducting Devices

  • question_answer
    The input signal given to a CE amplifier having a voltage gain of 150 is
    \[{{V}_{i}}=2\cos \left( 15t+\frac{\pi }{3} \right)\] The corresponding output signal will be    [NEET (Re) 2015]

    A)  \[300\cos \left( 15t+\frac{\pi }{3} \right)\]

    B)  \[75\cos \left( 15t+\frac{2\pi }{3} \right)\]

    C)  \[2\cos \left( 15t+\frac{5\pi }{3} \right)\]

    D)       \[300\cos \left( 15t+\frac{4\pi }{3} \right)\]

    Correct Answer: D

    Solution :

    Input signal of a CE amplifer, \[{{V}_{in}}=2\cos \left( 15t+\frac{\pi }{3} \right)\]
    Voltage gain \[{{A}_{v}}=150\]
    As CE amplifier gives phase difference of n between input and output signals.
    So        \[{{A}_{v}}=\frac{{{V}_{0}}}{{{V}_{in}}}\Rightarrow {{V}_{0}}={{A}_{v}}{{V}_{in}}\]
                \[{{V}_{0}}=150\times 2\cos \left( 15t+\frac{\pi }{3}+\pi  \right)\]
    \[V=300\cos \left( 15t+\frac{4\pi }{3} \right)\]


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