/أسبوع مجانًااختبار #390
❓ Quiz #390
20 سؤال
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السؤال 1
What is the primary function of a diode in a power electronics circuit?
A.
Amplification
B.
Bidirectional current flow
C.
Unidirectional current flow
D.
Energy storage
السؤال 2
Switching losses in a power electronic converter are primarily caused by:
A.
Conduction through the switch when it's ON.
B.
Leakage current when the switch is OFF.
C.
Finite rise and fall times of current and voltage during transitions.
D.
Parasitic capacitance of the inductor.
السؤال 3
In an ideal DC-DC buck converter, if the input voltage is V_in and the duty cycle is D, what is the approximate output voltage?
A.
V_in / D
B.
V_in * D
C.
V_in * (1 - D)
D.
V_in
السؤال 4
Which of the following describes the turn-off characteristic of a MOSFET most accurately?
A.
Slow due to minority carrier recombination.
B.
Fast due to majority carrier device operation.
C.
Requires forced commutation.
D.
Depends mainly on the load inductance.
السؤال 5
An IGBT combines the advantages of which two device types?
A.
BJT and Diode
B.
SCR and MOSFET
C.
MOSFET and BJT
D.
Thyristor and Diac
السؤال 6
What does PWM stand for in the context of power electronics?
A.
Power Wave Modulation
B.
Pulse Width Measurement
C.
Phase Wave Modification
D.
Pulse Width Modulation
السؤال 7
High ripple current in the output of a DC-DC converter can lead to:
A.
Increased efficiency.
B.
Reduced electromagnetic interference (EMI).
C.
Higher output voltage stability.
D.
Increased losses in passive components.
السؤال 8
Once an SCR is triggered into conduction, how can it be turned off?
A.
By applying a negative gate voltage.
B.
By removing the gate signal.
C.
By reducing the anode current below the holding current.
D.
By increasing the anode-cathode voltage.
السؤال 9
What is the primary goal when designing a power electronic converter regarding efficiency?
A.
Minimize input current.
B.
Maximize power factor.
C.
Minimize power losses.
D.
Maximize switching frequency.
السؤال 10
A DC-DC boost converter is primarily used to:
A.
Decrease the DC output voltage.
B.
Increase the DC output voltage.
C.
Invert the DC output voltage.
D.
Convert AC to DC.
السؤال 11
What is the main role of an inductor in a buck or boost converter?
A.
To block AC current.
B.
To filter out DC components.
C.
To store energy and smooth current.
D.
To generate voltage spikes.
السؤال 12
Which type of rectifier uses four diodes to convert AC to pulsating DC?
A.
Half-wave rectifier
B.
Center-tapped full-wave rectifier
C.
Bridge rectifier
D.
Voltage doubler rectifier
السؤال 13
A Voltage Source Inverter (VSI) typically produces an output with a controlled:
A.
Output current magnitude.
B.
Output voltage magnitude and frequency.
C.
Input voltage and current.
D.
Reactive power only.
السؤال 14
Conduction losses in a power switch are primarily determined by:
A.
Switching frequency and device capacitance.
B.
On-state resistance/voltage drop and current.
C.
Gate drive power.
D.
Off-state leakage current.
السؤال 15
What is the primary purpose of a snubber circuit in power electronics?
A.
To increase the switching frequency.
B.
To protect switching devices from overvoltage and overcurrent stresses.
C.
To amplify the control signal.
D.
To improve the power factor.
السؤال 16
What is another common name for a DC-DC converter in some contexts?
A.
Inverter
B.
Rectifier
C.
Chopper
D.
Cycloconverter
السؤال 17
The key difference between a thyristor (SCR) and a power diode is:
A.
Thyristors can block reverse voltage, diodes cannot.
B.
Thyristors are controllable switches, diodes are uncontrolled.
C.
Diodes have higher current ratings than thyristors.
D.
Thyristors generate less heat than diodes.
السؤال 18
Why is an input filter often used in power electronic converters connected to the grid?
A.
To increase the output power of the converter.
B.
To reduce electromagnetic interference (EMI) injected back into the grid.
C.
To decrease the input voltage ripple.
D.
To regulate the DC link voltage.
السؤال 19
Which type of power electronic converter directly converts AC power at one frequency and voltage to AC power at a different frequency and voltage without an intermediate DC link?
A.
Rectifier
B.
Inverter
C.
Cycloconverter
D.
Resonant converter
السؤال 20
In a half-bridge or full-bridge inverter, what is 'dead time' used for?
A.
To increase the output voltage.
B.
To prevent shoot-through currents in the bridge legs.
C.
To allow for accurate voltage sensing.
D.
To reduce switching losses.
الموجّه: Based on core concepts of power electronics
