Public sector engineering Organization
Test date 6th august
Subject TE(Electronics)
1. The potential difference between two similar charges
a)nil b)same
ans nil
2. Ideal transformer no losses
3. In DC motor which loss decreases with increase in load
a) friction and windage loss
b) Core
c)brush contact loss
d)None
Ans d
4. Constant current transformer should not have
a)moveable secondary winding
b)high resistance
c)primary and secondary winding surrounding core
d)A high resistance
Ans d
5. Main drawback of feedback system is:
a)Inaccuracy b)Inefficiency c)Insensitivity d)Instability
6. Pole shoes of DC machine fastened to pole core by
a)welding b)soldering c)steal clamp d)counter sunk
Ans d
7. Brushes on commutator are shifted from GNP to
a)obtain highest generated voltage b)Avoid sparking c)to increase generated efficiency d)to produce
sparking
8. Form factor is ratio of
a)avg to rms b)peak to rms c)rms to avg
Ans c
9. A.C. servomotor resembles
(a) two phase induction motor
(b) Three phase induction motor
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(c) direct current series motor
(d) universal motor
Ans: a
10.SCR is three junctions device.
11. full rectification needs -------------diodes
(a)four (b) two
Ans two
12. Conductor consist of _______________
a) free electrons
b)Excess of electron
c)holes
d)proton
13. .which transformer side has low cross sectional area
a) primary
b) secondary
c) high voltage
d) low voltage
ans c
14. which has low form factor
a) sine wave
b) square wave
c) Triangular wave..
d) rectified wave
Ans b
15. Silican atomic number is 14 its valency is
Ans 4
16.consversion of decimal number into bianary is called Multiplexer
17.Arrangment of data in specific order is called
a)data processing
b)data arrangement
c)data saving in memory
18. unit of potential volt
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19.unit of inductive susuceptace.
20.charge within Depletion region
21.which configuration is mostly used in circuits
a)npn
b)pnp
c)n-n
d)p-p
22.which one does not exibit negative resistance
Ans Fet
23.when covalent bond breaks
Ans holes and electrons pair produced
24. minimum time of pulse triggering of SCR
a) 10v
b)20v
c)30v
d)40v
25. Transient response of system
Ans Stored energy
26. Commercial effenciency of Transformer
a)zero
b)100%
ans A
27.whch one is not category of measurement
Ans validity
28. in n-type ______impurities is added
Ans Pentavalent
29. in transistor is transfer of
a)amplification
b)Switching
c)Rectifing
30. IBM/360 invinted
a)third generation
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b) first generation
c)1950
d)1990
31. Inverter as compare to oscillator
32. CompuServe is?????
33. For large power transformer best utilization of available core space can be made by using
Ans (stepped core section)
34. A Dc shunt Generator delivers 195A at 250V and the resistance of shunt field and armature field are
0.02Ω and 50Ω the emf generated will be
a)246v
b)270V
c)254V
d)290V
Solution Ish=Vsh/Rsh =250/50 =5A
I=Ish+IL Ia=5+195=200A Armature drop=IaRa=>200×0.02 =>4V
Generated EMF=V+IaRa =>Eb=250+200×0.02=>254V
35. A transformer has negative voltage regulation when its load power factor is
Ans (Zero )
36. electron exists in
Ans Outer most Shell
37. Transformer oil should be free from
Ans Moisture
38. Buchhloz Relay is used on
Ans Transformer protection
39. The unit charge is coulomb
40. Pole shoes of DC machine fastened to pole core by
Ans Counter Screw Sunk
41. Measurement define free from error
Ans Accuracy
42. shunt resistance of galvanometer increased
Ans current sensitivity decreased
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43. Meter can not be use for DC
Ans (Induction type)
44.use as null detector in Wheatstone bridge
Ans (galvanometer)
45. A moving Iron type ammeter has few turn of tick wire
Ans so that resistance is less
46 Charge on electron negative
47. advantages of Permanent magnet moving coil
Ans All
Opposite meaning of following words
48. Elegent
49. despondency
50.Prim
51.dissent
52.Vanquish
53. Cessation
54.Mawkwish
55.Graph between Voltage and current in pn junction is??
56.when all the terms in a row of Routh array are zero the characteristic equation has roots on
Ans the imaginary axis
57. Addition of poles in Transfer Function
Ans lead compensation
58.the speed of shunt Dc motor can be controlled by
Ans all
Analogy of the following
59. Blaster: skin
60 Stable horse
61 mangoose Snake
62 census population
63 insulin Daibaties
64 cloth dissolved
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65 aqueduct water
66. A 220V dc shunt motor takes a total current of 80A and runs at 800 rpm Resistance of Shunt field is
50Ω and that of armature 0.1Ω . The iron and friction losses amount to 1600W. What is the deriving
power of the motor?
a) 16050W
b) 14500W
c) 12600W
d) 18500W
Ans a
Solution Ish=Vsh/Rsh =220/50 =4.4A
I=Ish+Ia Ia=80-4.4=75.6A V=Eb+IaRa =>Eb=220-75.6×0.1=>212.44A
Deriving torque=Eb×Ia=>212.44×75.6=>16050W
67. Transformer transforms power
68. which insulator installed is dead ended
a)suspension
b)Discs type
69. By multiplying two with four we need how many operation
a)two
b)four
c)fifteen
70.the Scale of permanent magnet moving coil instrument is Uniform because it is Spring Controoled
Analytical
i) Bakeries wala Law
ii) 2 europian 4 american 3 asian wala Law
English Paragragh was related to Rediation
Please remember me in your prayers JazakAllah
Compiled by Engr Hamdan Saeed
Compiled by Engr Hamdan Saeed
