Physical electronics devices and ics miscellaneous

Physical electronics devices and ics miscellaneous

Easy Questions

Physical Electronics Devices and ICs

Physical electronics devices and ics miscellaneous
  1. The JFET in the circuit shown in figure has an IDSS = 10 mA and VP = 5 V. The value of the resistance RS for a drain current IDS = 6.4 mA is (select the nearest value)—










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    We know that IDS = IDSS …(a)
    Given that, IDS = 6.4 10–3 A
    VP = 5V
    IDSS = 10 10–3 A
    VGS =?

    6.4 10–3 = 10 10–31 -VGS2
    - 5

    1
    VGS    		= √.64= 8
    - 5

    or VGS = 1V
    Now, IDS RS = VGS = (1V)
    RS =
    1
    		= 156Ω
    6·4 × 10–3

    Since 156 Ω is very close to 150 Ω.
    Hence alternative (A) is correct answer.

    Correct Option: A

    We know that IDS = IDSS …(a)
    Given that, IDS = 6.4 10–3 A
    VP = 5V
    IDSS = 10 10–3 A
    VGS =?

    6.4 10–3 = 10 10–31 -VGS2
    - 5

    1
    VGS    		= √.64= 8
    - 5

    or VGS = 1V
    Now, IDS RS = VGS = (1V)
    RS =
    1
    		= 156Ω
    6·4 × 10–3

    Since 156 Ω is very close to 150 Ω.
    Hence alternative (A) is correct answer.

  1. In an FET as VGS is changed from zero to increasing reverse bias, the value of gm—








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    We know that

    gm = gm01 -VGS
    VP

    From the above relation it is clear that as VGS is changed from zero to increasing reverse bias, the value of gm decreases.

    Correct Option: B

    We know that

    gm = gm01 -VGS
    VP

    From the above relation it is clear that as VGS is changed from zero to increasing reverse bias, the value of gm decreases.

  1. Compared to the junction transistor, FET—
    1. Has a large gain bandwidth product
    2. Is less noisy
    3. Has less input resistance
    4. Has only majority carriers flow








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    As compare to BJT, FET is (i) Less noisy and (ii) Here only majority carrier flow.

    Correct Option: C

    As compare to BJT, FET is (i) Less noisy and (ii) Here only majority carrier flow.

  1. In amplifier applications FET is operated in the—








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    In amplifier application FET is operated in the controlled resistor region.

    Correct Option: A

    In amplifier application FET is operated in the controlled resistor region.

  1. VP is the pinch-off voltage for VGS = 0 in an FET. When the gate is reverse biased by VG S the pinch-off voltage—








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    Will be less than VPO, because when gate is reverse biased deplection width increases, which decreases the pinch-off voltage.

    Correct Option: A

    Will be less than VPO, because when gate is reverse biased deplection width increases, which decreases the pinch-off voltage.