Aircraft Electrical Systems Technician Exam – Full
Practice Test (100 Questions Solved)
1. What is the primary purpose of an aircraft generator or alternator?
A. To supply pneumatic power
B. To convert mechanical energy into electrical energy
C. To supply hydraulic pressure
D. To regulate bus voltage
Rationale: Generators/alternators transform engine-driven
mechanical rotation into usable electrical power.
2. What device prevents reverse current flow from the battery to the
generator?
A. Voltage regulator
B. Reverse current (cutout) relay
C. Solenoid contactor
D. Capacitor
Rationale: The cutout relay opens when generator voltage drops,
preventing battery discharge through the generator.
3. What is the “bus” in an aircraft electrical system?
A. Fuel distribution network
B. A common electrical distribution point
C. A high-voltage test point
D. The wiring harness
Rationale: A bus collects and distributes electrical loads throughout
the aircraft.
4. What is the main advantage of an alternator over a generator?
,A. Higher weight
B. Lower output at idle
C. High output at low RPM due to rectification
D. Lower efficiency
Rationale: Alternators maintain high current output even at low
engine speeds.
5. The frequency of AC systems in most transport aircraft is:
A. 50 Hz
B. 400 Hz
C. 800 Hz
D. 60 Hz
Rationale: 400 Hz allows smaller, lighter electrical components.
6. What component rectifies AC to DC?
A. Transformer
B. Diode or rectifier bridge
C. Capacitor
D. Relay
Rationale: Diodes permit one-way electrical flow, converting AC to DC.
7. What does an electrical load meter measure on DC aircraft?
A. Bus voltage
B. Generator current output
C. Battery temperature
D. Alternator frequency
Rationale: DC loadmeters display generator current to indicate system
load.
8. What does an ammeter wired in the battery lead display?
, A. Bus voltage
B. Battery charge or discharge rate
C. Transformer temperature
D. Generator field current
Rationale: Placement in the battery lead shows current entering or
leaving the battery.
9. Bonding jumpers are used to:
A. Secure fuel lines
B. Increase resistance
C. Reduce static electricity and provide electrical continuity
D. Provide insulation
Rationale: Bonding equalizes electrical potential and prevents arcing
or static buildup.
10. What tool is used to measure insulation resistance in aircraft
wiring?
A. Voltmeter
B. Ammeter
C. Megohmmeter (Megger)
D. Hydrometer
Rationale: MGG testers apply high voltage to test insulation integrity.
11. The primary purpose of a voltage regulator is to:
A. Increase electrical load
B. Control frequency
C. Maintain generator/alternator output voltage within limits
D. Provide short-circuit protection
Rationale: Regulators adjust field current to keep voltage stable under
varying loads.
Practice Test (100 Questions Solved)
1. What is the primary purpose of an aircraft generator or alternator?
A. To supply pneumatic power
B. To convert mechanical energy into electrical energy
C. To supply hydraulic pressure
D. To regulate bus voltage
Rationale: Generators/alternators transform engine-driven
mechanical rotation into usable electrical power.
2. What device prevents reverse current flow from the battery to the
generator?
A. Voltage regulator
B. Reverse current (cutout) relay
C. Solenoid contactor
D. Capacitor
Rationale: The cutout relay opens when generator voltage drops,
preventing battery discharge through the generator.
3. What is the “bus” in an aircraft electrical system?
A. Fuel distribution network
B. A common electrical distribution point
C. A high-voltage test point
D. The wiring harness
Rationale: A bus collects and distributes electrical loads throughout
the aircraft.
4. What is the main advantage of an alternator over a generator?
,A. Higher weight
B. Lower output at idle
C. High output at low RPM due to rectification
D. Lower efficiency
Rationale: Alternators maintain high current output even at low
engine speeds.
5. The frequency of AC systems in most transport aircraft is:
A. 50 Hz
B. 400 Hz
C. 800 Hz
D. 60 Hz
Rationale: 400 Hz allows smaller, lighter electrical components.
6. What component rectifies AC to DC?
A. Transformer
B. Diode or rectifier bridge
C. Capacitor
D. Relay
Rationale: Diodes permit one-way electrical flow, converting AC to DC.
7. What does an electrical load meter measure on DC aircraft?
A. Bus voltage
B. Generator current output
C. Battery temperature
D. Alternator frequency
Rationale: DC loadmeters display generator current to indicate system
load.
8. What does an ammeter wired in the battery lead display?
, A. Bus voltage
B. Battery charge or discharge rate
C. Transformer temperature
D. Generator field current
Rationale: Placement in the battery lead shows current entering or
leaving the battery.
9. Bonding jumpers are used to:
A. Secure fuel lines
B. Increase resistance
C. Reduce static electricity and provide electrical continuity
D. Provide insulation
Rationale: Bonding equalizes electrical potential and prevents arcing
or static buildup.
10. What tool is used to measure insulation resistance in aircraft
wiring?
A. Voltmeter
B. Ammeter
C. Megohmmeter (Megger)
D. Hydrometer
Rationale: MGG testers apply high voltage to test insulation integrity.
11. The primary purpose of a voltage regulator is to:
A. Increase electrical load
B. Control frequency
C. Maintain generator/alternator output voltage within limits
D. Provide short-circuit protection
Rationale: Regulators adjust field current to keep voltage stable under
varying loads.
