Electronic Devices and Circuits Mid - I, August - 2012

1.A breakdown which is caused by cumulative multiplication of carriers through field-induced impact ionization occurs in
  • Zener diode
  • Tunnel diode
  • Varactor diode
  • Avalanche diode
Answer: D
2.A rectifier is used to
  • Convert a.c voltage to d.c voltage
  • Convert d.c voltage to a.c voltage
  • Both (a) and (b)
  • Convert voltage to current
Answer: A
3.The bridge rectifier requires
  • 2 diodes
  • 3 diodes
  • 4 diodes
  • 8diodes
Answer: C
4.In most transistors, the collector region is made physically large than the emitter region
  • For dissipating heat
  • To distinguish it from other regions
  • As it is sensitive to ultraviolet rays
  • To reduce resistance in the path of flow of electrons
Answer: A
5.In a PNP transistor with normal bias, the emitter junction
  • Is always reverse biased
  • Offers very high resistance
  • Offers a low resistance
  • Remains open
Answer: C
6.The arrow head on a transistor symbol indicates
  • Direction of electron current in the emitter
  • Direction of hole current in the emitter
  • Diffusion current in the emitter
  • Drift current in the emitter
Answer: A
7.The common emitter transistor circuit has
  • High gain
  • Low gain
  • Negligible gain
  • Zero gain
Answer: A
8.In a PNP transistor , the electrons flow into the transistor at the
  • Collector only
  • Emitter only
  • Emitter and base
  • Collector and base
Answer: D
9.The quiescent point of a transistor biasing circuit implies
  • Zero bias
  • No output
  • No distortion
  • No input signal
Answer: C
10.The collector current for the CE circuit is given IC = β IB + (I + β) ICO. The three variables β, IB and ICO
  • Increase with rise in temperature
  • Increase with fall in temperature
  • Decrease with rise in temperature
  • Decrease with fall in temperature
Answer: A
11.The forbidden energy gap for germanium is ________.
Answer: 0.782 eV
12.In a PN-Junction , the region containing the uncompensated acceptor and donor ions is called _________________.
Answer: Depletion region
13.When holes leave the p-material to fill electrons in the n-material, the process is called _________.
Answer: Diffusion
14.The condition to prevent thermal runaway is given by ______________.
Answer: (∂Pc/∂Tj)<(1/o)
15.An avalanche breakdown diode has __________ temperature coefficient.
Answer: positive
16.The ripple factor of a half-wave rectifier is __________.
Answer: 1.21
17.The ripple factor of π-section (CLC) filter is _______________.
Answer: 5700/L.C1.C2.RL
18.Line regulation is _________________.
Answer:
19.Stability factor ‘S’ is approximately unity for __________ bias.
Answer: Self
20.For normal amplification, the Q point should be established in the __________ region.
Answer: Active