Electronic Devices and Circuits Mid - I, September - 2014

1.A PN Junction diode dynamic conductance is directly proportional to
  • the applied voltage
  • the temperature
  • its current
  • the thermal voltage
Answer: C
2.An electron device means the device in which the conduction of electrons takes place through
  • a gas
  • vacuum
  • a semiconductor
  • a gas, semiconductor & vacuum
Answer: D
3.Avalanche breakdown is primarily dependent on the phenomenon of
  • Collision
  • doping
  • ionization
  • recombination
Answer: A
4.The reverse current of a silicon diode is
  • Highly bias voltage sensitive
  • highly temperature sensitive
  • both bias voltage and temperature sensitive
  • Independent of bias voltage & temperature
Answer: B
5.The negative resistance in a tunnel diode
  • is maximum at the peak point of the characteristic
  • is available b/w the peak & valley points
  • is maximum at the valley point
  • may be improved by the use of reverse bias
Answer: B
6.In saturation region in an NPN transistor
  • VCB is –ve & VBE is +ve
  • VCB is +ve &VBE is –ve
  • both VCB & VBE are +ve
  • both VCB & VBE are –ve
Answer: A
7.The symbol α in terms of BJT denotes
  • ratio of IB and IC
  • ratio of VBE and VCE
  • ratio of IE and IC
  • ratio of IC and IE
Answer: D
8.Two transistors back to back form
  • diode
  • transistor
  • UJT
  • SCR
Answer: D
9.The following is not an application of varactor diode
  • Parametric Amplifier
  • Frequency Tuner
  • voltage controlled oscillator
  • phase shifter
Answer: D
10.Ripple factor of an ideal rectifier is
  • 1
  • 0
  • infinity
  • none of the above
Answer: B
11.A Full wave rectifier needs at least -------------- diodes
Answer: 2 diodes
12.Reverse resistance of a diode is of the order of ---------- ohms
Answer: Mega
13.Zener diodes have ------------------ temperature coefficient
Answer: negative
14.A Tunnel diode is a ---------------- doped PN junction
Answer: heavily
15.The purpose of -------------------- is decrease ripple in a rectitier circuit.
Answer: filter
16.The most heavily doped region in a BJT is -----------------
Answer: emitter
17.The knee voltage for silicon PN Junction is -------- Volt
Answer: 0.7 volts
18.A UJT has ----------- PN junction
Answer: one
19.SCR is the oldest & widely used member of ---------------- family
Answer: Thyristor
20.Rectifier Converts ------------ to -------------
Answer: AC to DC