Physical electronics devices and ics miscellaneous


Physical electronics devices and ics miscellaneous

Physical Electronics Devices and ICs

Direction: In the voltage regulator circuit shown below. The zener diode current is to be limited to the range 5 ≤ i Z ≤ 100 mA.

  1. The range of possible load current—









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    From figure,

    I =
    6.3 – Vz
    =
    6.3 – 4.8

    12Ω12

    =
    1.5 V
    = 125 mA
    12 kΩ

    The range of IL: when, Iz = 5 mA
    IL = I – Iz = 125 – 5 = 120 mA
    and range, when, Iz = 100 mA
    IL = 125 – 100 = 25 mA
    Hence the range of IL is 25 mA ≤ IL ≤ 120 mA

    Correct Option: B

    From figure,

    I =
    6.3 – Vz
    =
    6.3 – 4.8

    12Ω12

    =
    1.5 V
    = 125 mA
    12 kΩ

    The range of IL: when, Iz = 5 mA
    IL = I – Iz = 125 – 5 = 120 mA
    and range, when, Iz = 100 mA
    IL = 125 – 100 = 25 mA
    Hence the range of IL is 25 mA ≤ IL ≤ 120 mA


  1. In the voltage regulator circuit shown below. The power rating of zener diode is 400 mW. The value of RL that will establish maximum power in Zener diode is—











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    Iz (max) =
    P
    =
    400 mW
    = 40 mA
    VZ10 V

    Iz + IL =
    20 – VZ
    =
    20 - 10
    = 45 mA
    222222

    IL (min) = 45 – Iz = 45 – 40 = 5 mA
    Now,
    RL =
    VZ
    =
    10 V
    = 2 kΩ
    IL (min) 5 mA

    Correct Option: B

    Iz (max) =
    P
    =
    400 mW
    = 40 mA
    VZ10 V

    Iz + IL =
    20 – VZ
    =
    20 - 10
    = 45 mA
    222222

    IL (min) = 45 – Iz = 45 – 40 = 5 mA
    Now,
    RL =
    VZ
    =
    10 V
    = 2 kΩ
    IL (min) 5 mA



  1. In the voltage regulator shown below the power dissipation in the zener diode is—











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    Since in the given problem RZ is zero. so, in order to calculate the power dissipation across the zener diode. We must calculate the current flowing in zener diode
    Where, Vth = Thevenin equivalent voltage
    Rth = Thevenin equivalent resistance

    Vth =
    75
    = 50 .
    1

    75 + 1503

    =
    50
    V > VZ
    3

    Rth = 150 || 75 =
    150 × 75
    150 + 75

    = 50 kΩ
    iZ =
    Vth
    =
    50/3

    Rth + RL50 kΩ

    = 0.33 mA
    Now PZ = VZ. iZ = 15 × 0.33 mA
    = 0.5 mW
    Hence alternative (D) is the correct choice.

    Correct Option: D

    Since in the given problem RZ is zero. so, in order to calculate the power dissipation across the zener diode. We must calculate the current flowing in zener diode
    Where, Vth = Thevenin equivalent voltage
    Rth = Thevenin equivalent resistance

    Vth =
    75
    = 50 .
    1

    75 + 1503

    =
    50
    V > VZ
    3

    Rth = 150 || 75 =
    150 × 75
    150 + 75

    = 50 kΩ
    iZ =
    Vth
    =
    50/3

    Rth + RL50 kΩ

    = 0.33 mA
    Now PZ = VZ. iZ = 15 × 0.33 mA
    = 0.5 mW
    Hence alternative (D) is the correct choice.


  1. In the voltage regular circuit shown below the maximum load current iL that can be drawn is—











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    At regulated power supply i s =
    30 – 9
    = 1.4 mA
    15 × 103

    Therefore iL ≤ is = 1.4 mA

    Correct Option: A

    At regulated power supply i s =
    30 – 9
    = 1.4 mA
    15 × 103

    Therefore iL ≤ is = 1.4 mA



  1. If P is passivation, Q is n-well implant, R is metallization and S is source/drain diffusion, then the order in which they are carried out in a standard n-well CMOS fabrication process is—









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    NA

    Correct Option: B

    NA