TRADE
THEORY
ELECTONIC MECHANIC IV SEM
1.Which
layer of transistor is heavily doped?
a)Emitter
region b) base region c) collector region d) gate
2.In
NPN transistor the collector current is_____
a)Zero b) low c) medium d) high
3.Which
type of coupling is used in power amplifiers?
a)RC
coupling b) Transformer coupling c) LC
coupling d) Direct coupling
4. the current gain of a common base amplifier is____
a)IC/IE b) IE/IC c) IB/IC d)IC/IB
5. the regenerative feedback is also called as
a)Negative feedback b)positive feedback c) current
feedback d) voltage feedback
6. the unit of output impedance of a transistor
is______
a) ampere b) volt c) ohm d) mho
7. Which oscillator uses split inductor in the tank
circuit?
a) Wein bridge Oscillator b) RC phase shift Oscillator c) Colpitts
Oscillator d) Hartley Oscillator
8) how many stable state has monostable multivibrator?
a)One b)two c)three d)four
9. the basic components required for a clamping
circuit is________
a)Diode, capacitor and resistor b) Diode, capacitor
and transistor c) Diode, capacitor and
inductor d) Diode, capacitor and transformer
10. in which type of the clipper, the negative half
cycles of the input voltage is removed?
a) Positive clipper b) negative clipper c) biased
clipper d) combination clipper
11. the input impedance of FET is____
a)Zero b) low
c) medium d) high
12. SCR acts as a switch when it is_____
a)Forward biased b)reverse biased c) below cut off d)
above saturation
13.IC 555 can NOT be used in______
a) Voltage controlled oscillator b) one shot
multivibrator c) timer d) amplifier
14. a circuit which compares a signal voltage at one
output of an op-amp with known reference voltage at the other input is
called_______
a) Integrator
b) comparator c) differentiator d) operational amplifier
15. if the gain of op-amp is set lower, the bandwidth
of the amplifier will be_____
a) Higher b) lower c) medium d) no change
16. which device does not have the gate terminal
a) TRIAC b) FET
c) SCR d) DIAC
17. which is a trigger device
a) TRIAC b) FET
c) SCR d) DIAC
18. which semiconductor device acts like a diode and
two resistors
a) TRIAC b) UJT
c) SCR d) DIAC
19.FET is a____
a) Voltage controlled device b) current controlled device c) power
controlled device d) sensor controlled device
20. High power transistors are provided with____
a) Small collector region b) plastic package c) heat sink
d) sleeves
21. the terminals of TRIAC are_____
a) Collector, emitter, base b) base1, base2, emitter c) anode, cathode, gate d) MT1, MT2, gate
22. what is the function of gate in SCR?
a)To provide DC bias
b) ON SCR with a small gate current c) supply the load current through
gate d)rectify the output- voltage
23. which of the following is NOT applicable to UJT?
a) As an AF amplifier b) as oscillator c) as timing
circuits d) bistable circuits
24. Expansion of IGBT_____
a) Insulated Gate Bipolar Transistor b) Integrated
Gate Bipolar Transistor
c) Insulated Gate Bidirectional Transistor d) Integrated
Gate Bidirectional Transistor
25. which of the following is a unipolar device
a)BJT b) IGBT
c) GTO d) MOSFET
26. which is light sensitive sensors?
a) LDR b) RTD c) VDR d) SCR
27.Which LED emits invisible light
a) Infrared LED b) Laser LED c) Bi colour LED d) Tri
colour LED
28. Name the reverse current that follows through a
photo diode?
a) Forward current b) holding current c) leakage current d) Dark current
29.which colour LED has the highest forward voltage
drop?
a) Orange b) yellow c) red d) green
30.the example of passive photo semiconductor
is_______
a) Photo resistor b) Solar cell c) Photo-voltaic cell d) secondary cell
31. the thickness of PCB’s used for SMD is
between........
a)0.7 and 0.8 mm
b) 0.8 and 1.00mm c) 1.0 and 1.2
mm d) 1.2 and 1.4 mm
32. In SMD , the wattage required for soldering iron
is___
a) 25 or 50 watts b) 15 or 25 watts c) 15 or 35 watts
d) 10 or 50 watts
33. NOR gate is a combination of __
a) two OR gate b) OR gate and AND gate c) OR gate and
NOT gate d)AND gate and NOT gate
34. The Boolean expression Y= 
is for_____
is for_____
a) NOT gate b) AND gate c) NOR gate d) NAND gate
35. The following truth table is for which gate?
|
A
|
B
|
Y
|
|
0
|
0
|
0
|
|
0
|
1
|
1
|
|
1
|
0
|
1
|
|
1
|
1
|
1
|
a)
OR b) AND c) NAND D) EXOR
36.What is the base of octal number?
a)2 b) 8 c) 10
d) 16
37.A logic gate for which there is “HIGH” output when
anyone or both the inputs are “LOW ” is
a) OR b) AND c) NAND d)NOR
38.Name the following circuit
a) multiplexer b) de-multiplexer
c)combinational d) encoder
39.combination of two half adder is
a) full adder b) multiplexer c) de-multiplexer d) encoder
40.in JK flip flop , if J=1 and K=1 what is the value
of Q output
a) 1 b) 0 c) no change d) toggles
41. what is the name of the flip flop which is having
a single input
a) multivibrator b) D flip flop c) JK flip flop d)
clocked RS flip flop
42. which is used to construct a counter
a) AND gate b)
OR gate c) NAND gate d) Flip flop
43. A register is a group of flip flops and it stores
binary bits. How many flip flops are required to store 8 binary bits
a) 2 b) 4 c)
8 d) 16
44. in counters how the flip flops are triggered?
a) By using a multivibrator b) by the clock pulse
provided for each flip flops c) by a separate triggering circuit d) by the
previous flip flop
45. registers are used to ________
a) count binary number
b) store hexadecimal number c)
store binary number d) count hexadecimal number
46. the DC operating voltage of IC 555 is_________
a)3 to 10 v b)
5 to 18 v c) 1 to 5 v d ) -5v to +5 v
47. to increase the output pulse width of a IC 555
monostable multivibrator increase________
a) R and C value
b) trigger voltage c) VCC d) only
C value
48. application of bistable multivibrator________
a) electronic piano
b) timer c)
signal injector d) counters
49. the most common base material used for making IC’s
is
a) germanium b) silicon c) carbon d) gallium
50. the negative feedback used in op- amp_______
a) makes the amplifier stable b) increase the
frequency response c) prevent it from
producing oscillations d) increase the gain
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