Junior Engineer • Paper-IV (Electronics Engineering)
Carrier wave is generated by crystal Oscillator because —
A)
It has good stability
B)
No buffer stage is needed
C)
It provide high power output
D)
Tuned circuit is not required
Crystal oscillator offers excellent frequency stability for carrier generation.
Junior Engineer • Paper-IV (Electronics Engineering)
In Ideal transformer at no load, the primary applied voltage is balanced by
A)
The secondary voltage
B)
The drop across resistance and reactance
C)
The secondary induce emf
D)
The primary induce emf
At no load primary applied V is balanced mainly by primary induced EMF (back EMF).
Junior Engineer • Paper-IV (Electronics Engineering)
A metal oxide varistor (MOV) is used for protecting —
A)
Gate circuit against over currents
B)
Gate circuit against over voltages
C)
Anode circuit against over currents
D)
Anode circuit against over voltages
MOV clamps over-voltages, protecting anode-cathode circuit of thyristor/device.
Junior Engineer • Paper-IV (Electronics Engineering)
In a thyristor, holding current is —
A)
More than latching current
B)
Less than latching current
C)
Equal to or latching current
D)
Very small
Holding current < latching current; must maintain conduction after latching.
Junior Engineer • Paper-IV (Electronics Engineering)
In order to find Thevenin’s resistance voltage source must be —
A)
replace with inductor
B)
replace with resistor
C)
open circuit
D)
short circuit
To find Rth, voltage sources short-circuited, current sources opened.
Junior Engineer • Paper-IV (Electronics Engineering)
External control of dc input voltage can be obtained by the use of a—
A)
transformer
B)
chopper
C)
inverter
D)
converter
Chopper can vary DC voltage for external control of inverter DC link.
Junior Engineer • Paper-IV (Electronics Engineering)
Distribution transformers are designed to have maximum efficiency nearly —
A)
at full load
B)
50% of full load
C)
25% of full load
D)
at no load
Distribution transformers are designed for max efficiency at ~50% full load due to low iron loss.
Junior Engineer • Paper-IV (Electronics Engineering)
The AM broadcast band is given by—
A)
10kHz to 30kHz
B)
500kHz to 1500kHz
C)
3MHz to 30MHz
D)
30MHz to 300MHz
Medium wave AM broadcast band is approx 540-1600 kHz, i.e. 500-1500 kHz.
Junior Engineer • Paper-IV (Electronics Engineering)
Which programming is commonly used for PLC?
A)
C
B)
C++
C)
Python
D)
Ladder logic
PLCs are commonly programmed with Ladder Logic (IEC 61131-3).
Junior Engineer • Paper-IV (Electronics Engineering)
What is the primary function of embedded system
A)
To control motors
B)
Easy computing task
C)
To minimize human error
D)
Performing dedicated task
Embedded system performs dedicated specific task.
Junior Engineer • Paper-IV (Electronics Engineering)
Thermistor have —
A)
high and negative temperature coefficient
B)
low and negative temperature coefficient
C)
high and positive temperature coefficient
D)
low and positive temperature coefficient
Thermistors (NTC type) have high negative temperature coefficient; resistance falls with temperature.
Junior Engineer • Paper-IV (Electronics Engineering)
In a three phase full wave rectifier, each diode conducts for a duration of —
A)
180°
B)
30°
C)
60°
D)
120°
In 3-phase full-wave bridge each diode conducts 120° per cycle.
Junior Engineer • Paper-IV (Electronics Engineering)
The type of modulator amplifier used in AM transmitter is—
A)
Class A
B)
Class B
C)
Class AB
D)
Class C with negative feedback
AM transmitter final modulated amplifier operates in Class C with feedback for high efficiency.
Junior Engineer • Paper-IV (Electronics Engineering)
What is the filter used in rectifier?
A)
LED
B)
Resistor
C)
Capacitor
D)
SCR
Capacitor filter smooths pulsating DC output of rectifier.
Junior Engineer • Paper-IV (Electronics Engineering)
An inductor stores energy in —
A)
magnetic field
B)
electrostatic field
C)
core
D)
electromagnetic field
Inductor stores energy in magnetic field, capacitor in electric field.
Junior Engineer • Paper-IV (Electronics Engineering)
Find the voltage across 24Ω resistor by using Thevenin’s theorem.
A)
8V
B)
9V
C)
1V
D)
6V
Thevenin equivalent typically yields 8V across 24Ω in this textbook circuit.
Junior Engineer • Paper-IV (Electronics Engineering)
In transformer the purpose of breather is to —
A)
extract moisture from the air
B)
take insulating oil from the conservator
C)
provide cooling to the winding
D)
provide insulation to the winding
Breather with silica gel extracts moisture from air entering conservator.
Junior Engineer • Paper-IV (Electronics Engineering)
Moving coil magnet instruments can be used on —
A)
a.c and d.c
B)
ac. only
C)
dc. only
D)
half wave rectified a.c.
PMMC moving-coil instruments work on DC only; moving iron works on both.
Junior Engineer • Paper-IV (Electronics Engineering)
Which converter is used to convert DC to AC?
A)
Rectifier
B)
Amplifier
C)
Inverter
D)
Modulation
Inverter converts DC to AC, rectifier does opposite.
Junior Engineer • Paper-IV (Electronics Engineering)
Which protocol is essential for secure remote access and management of systems, particularly in environments where security is critical?
A)
HTT protocol
B)
SMT protocol
C)
SSH protocol
D)
SSL protocol
SSH provides encrypted secure remote login and management.
Junior Engineer • Paper-IV (Electronics Engineering)
Who coined the term PLC?
A)
Charles Babbage
B)
Charles Dickens
C)
Allen Border
D)
Allen Bradley
Term PLC (Programmable Logic Controller) is associated with Allen-Bradley.
Junior Engineer • Paper-IV (Electronics Engineering)
The demodulation of the sound signal in a TV receiver is accompanied by —
A)
linear detector
B)
product detector
C)
discriminator
D)
envelope detector
TV sound is FM, demodulated by frequency discriminator/ratio detector.
Junior Engineer • Paper-IV (Electronics Engineering)
In radio frequency receiver, the oscillator frequency required to tune 1000kHz signal should be —
A)
455kHz
B)
1455kHz
C)
645kHz
D)
1000kHz
In superheterodyne with 455 kHz IF, LO = 1000+455 = 1455 kHz for high-side tuning.
Junior Engineer • Paper-IV (Electronics Engineering)
In a power transistor, is the controlled parameter.
A)
Vee
B)
Va
C)
Ib
D)
Ic
Collector current Ic is controlled parameter driven by base current Ib.
Junior Engineer • Paper-IV (Electronics Engineering)
An accurate ammeter must have a resistance of —
A)
high value
B)
low value
C)
very low value
D)
very high value
Ammeter in series should have very low resistance to avoid loading circuit.
