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ECE :: Electronic Devices and Circuits

  1. What is the effect of cut in voltage on the wave form of output as compared to input in a semiconductor diode?

  2. A.
    The duration of output waveform is less than 180°
    B.
    Output voltage is less than input voltage
    C.
    Output voltage is more than input voltage
    D.
    Both (a) and (b)

  3. As temperature increases the number of free electrons and holes in an intrinsic semiconductor

  4. A.
    increases
    B.
    decreases
    C.
    remains the same
    D.
    may increase or decrease

  5. At room temperature kT = 0.03 eV.

  6. A.
    True
    B.
    False

  7. Assertion (A): A JFET behaves as a resistor when VGS < VP.

    Reason (R): When VGS < VP, the drain current in a JFET is almost constant.

  8. A.
    Both A and R are true and R is correct explanation of A
    B.
    Both A and R are true but R is not a correct explanation of A
    C.
    A is true but R is false
    D.
    A is false but R is true

  9. In a reverse biased P-N junction, the current through the junction increases abruptly at

  10. A.
    zero voltage
    B.
    1.2 V
    C.
    0.72 V
    D.
    breakdown voltage

  11. Dielectric strength of polythene is around

  12. A.
    10 kV/mm
    B.
    40 kV/mm
    C.
    100 kV/mm
    D.
    140 kV/mm

  13. Resistivity of hard drawn copper is

  14. A.
    less than that of annealed copper
    B.
    more than that of annealed copper
    C.
    same as that of annealed copper
    D.
    decreasing when temperature increases

  15. The channel of JFET consists of

  16. A.
    p type material only
    B.
    n type material only
    C.
    conducting material
    D.
    either p or n type material

  17. In a bipolar junction transistor adc = 0.98, ICO= 2 μA and 1B = 15 μA. The collector current IC is

  18. A.
    635 mA
    B.
    735 mA
    C.
    835 mA
    D.
    935 mA

  19. The voltage across the secondary of the transformer in a half wave rectifier with a shunt capacitor filter is 50 volts. The maximum voltage that will occur on the reverse biased diode will be

  20. A.
    100 V
    B.
    88 V
    C.
    50 V
    D.
    25 V