JEE Main & Advanced Physics Semiconducting Devices Question Bank Valve Electronics (Diode and Triode)

  • question_answer
    A triode has a mutual conductance of \[2\times {{10}^{-3}}mho\] and an amplification factor of 50. The anode is connected through a resistance of \[25\times {{10}^{3}}\] ohms to a 250 volts supply. The voltage gain of this amplifier is                    [MP PMT 1989]

    A)            50  

    B)            25

    C)            100

    D)            12.5

    Correct Answer: B

    Solution :

                       Using \[{{A}_{V}}=\frac{\mu }{1+\frac{{{r}_{p}}}{{{R}_{L}}}}\]and \[\mu ={{r}_{p}}\times {{g}_{m}}\]                    \[\Rightarrow {{r}_{p}}=\frac{\mu }{{{g}_{m}}}=\frac{50}{2\times {{10}^{-3}}}=25\times {{10}^{3}}\Omega \]                    \[\therefore {{A}_{v}}=\frac{50}{1+\frac{25\times {{10}^{3}}}{25\times {{10}^{3}}}}=25.\]


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