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WorksheetsAutomotive Electrical Systems: a 2021 Revision Aid
Total questions: 40
Worksheet time: 20mins
What would be the most suitable test to carry out if a battery does not charge?
Check all the lamps have the correct rating
Check for corrosion on the starter motor Positive connection
Carry out an Alternator Current Output Test
Test the Specific Gravity of the electrolyte
When conducting an alternator current output test what is the most common meter reading?
36 Volts
36 Ohms
36 Watts
36 Amps
What will cause the Specific Gravity (SG) of a battery to vary?
The state of charge of the battery
The internal resistance of the battery
The relative outside air pressure
The number of consumers switched on
If a windscreen wiper does not operate which of the following would you check first?
The wiper blade
The windscreen rain sensor
The third brush in the motor
The circuit fuse
In a 12 Volt car battery in good condition, what is the minimum cranking voltage that should be seen when tested?
8.7 Volts DC
10.5 Volts DC
14.5 Volts AC
12.36 Volts DC
Why does the battery supply a small voltage even when all circuits are switched off?
To maintain a small working temperature in the battery
To ensure the glow plugs are warm for enhanced cold starting in winter
To prevent component memory loss in the radio
To maintain constant monitoring of the Tyre Pressure Monitoring System (TPMS)
Which component in an alternator converts AC Voltage into DC Voltage?
The regulator
The armature
The commutator
The rectifier
Which electrical component contains brushes, parking cam and worm gears?
The Alternator
The Starter Motor
The Wiper Motor
The Automatic Gearbox
In an alternator, which electronic components are used to convert AC into DC?
Diodes
Resistors
Transistors
Thermistors
Where in the electrical circuit are you most likely to find a Darlington Pair?
An ABS Reluctor Ring
A Double-ended Wasted Spark Ignition Coil
A Voltage Regulator
A pre-engaged starter motor
If a copper wire has a rating of 28/0.30mm which of the following is true?
Maximum current rating of 28 Amps through a 0.30mm cable
28 volt maximum load protected by a 0.30mm fuse
28 strand cable with a 0.30mm overall diameter
28 strands each of 0.30mm diameter
If the headlamps of a car are dim what would be your first check?
Damage to the headlamp lens
Poor earth connection
Corroded headlamp reflector
The supply voltage
Which of the following is the most important safety factor when handling a Quartz-Halogen lamp?
Do not touch the bulb envelope
Check the lamp rating
Do not touch the terminals
Use electrically conductive paste on the mounting flange
How would you diagnose a Main Lighting Switch fault?
Front and rear indicators work normally, side repeater lamp fails to operate
Side and rear lamps work normally, Main and Dip fail to operate
Front spotlights operate normally, rear fog lights fail to operate
All lights fail to operate
What test would you perform if the starter motor turns over very slowly when starting the engine?
A Current Flow test
A Continuity test with an Ohms meter
A Volt Drop test
A Cylinder Compression test
Which part of an alternator produces the output voltage?
The Rotor
The Casing
The Slip Rings
The Stator
Which part of an alternator provides the energising voltage or field current?
The Rotor
The Casing
The Slip Rings
The Stator
Which part of an alternator allows for the connection of the brushes?
The Rotor
The Casing
The Slip Rings
The Stator
Which part of an alternator allows the unit to be mounted on the engine?
The Rotor
The Casing
The Slip Rings
The Stator
What is the generic name for the liquid or gel in a battery?
Troglodyte
Anthracite
Coprolite
Electrolyte
What is a Thermistor?
A heat-sensitive windscreen condensation sensor
A heat-sensitive transistor
A resistor whose resistance changes with temperature
A diode whose resistance changes with temperature
Which regulations control the maximum output of headlamps?
Vehicle Lighting Regulations
VOSA/MOT Lighting Regulations
EU Lighting Regulations (Euro 6)
Construction and Use Regulations
How is a Voltmeter connected to carry out tests?
In series
In combination
In parallel
In isolation
How is an Ammeter connected to carry out tests?
In series
In combination
In parallel
In isolation
How is an Ohmmeter connected to carry out tests?
In series
In combination
In parallel
In isolation
When disconnecting a battery, which terminal is removed first?
Positive
Ground
Neutral
It does not matter
When is it safe to disconnect a coded radio?
When the main battery has been fully discharged
When you have written permission from the owner
When the car battery is fully charged
When the security code is known
Which of the following is true for an NTC Thermistor?
Resistance remains constant at all temperatures
Resistance increases as temperature decreases
Resistance decreases as temperature decreases
Resistance is useless
Which of the following is true for a PTC Thermistor?
Resistance remains constant at all temperatures
Resistance increases as temperature decreases
Resistance decreases as temperature decreases
Resistance is useless
Which of the following is the most likely cause of excessively high, or low alternator output voltage?
Corrosion on the slip rings
Faulty Rectifier
Faulty Stator
Faulty Regulator
What type of starter motor uses a solenoid?
Bendix
Epicyclic
Cartridge
Pre-engaged
Which electronic component can be considered as an electrical one-way valve?
A Transistor
A Diode
A Potentiometer
A Capacitor
Which of the following is correct regarding Ohms Law?
Volts = Amps Plus Ohms
Volts - Amps divided by Ohms
Volts = Amps times Ohms
Volts = Amps minus Ohms
Why does a wiper motor have a 3rd brush?
To allow for 2-speed operation
To make sure the commutator is kept clean
To allow for intermittent operation
To allow for automatic operation
Which of the following is an electro-mechanical switch consisting of a coil of wire and a movable metal bar?
A Potentiometer
A Thyristor
A Knock Sensor
A solenoid
When does voltage flow in a circuit?
When there is a battery connected
When there is potential difference
When there is a complete circuit
When there is a load connected
How would you calculate the overall resistance in a series circuit containing a number of resistors?
Use the Mean of all the values of all the resistors
Add the values of all the resistors together
Use the Median of all the resistors
Divide the Range by the number of resistors
Which of the following equations is correct to find the overall, or Equivalent, resistance in a parallel circuit?
Req = (R1 x R2) minus (R1 + R2)
Req = (R1 x R2) times (R1 + R2)
Req = (R1 x R2) plus (R1 + R2)
Req = (R1 x R2) divided by (R1 + R2)
Why should you not connect a Voltmeter in series with a high current circuit?
It would seriously damage the meter
It does not have the correct type of connector
It would cause an excessive back EMF
It may give an incorrect reading or value
What device is fitted to a pre-engaged starter motor to disconnect if from the flywheel when the engine starts?
A Bendix Spring
A Pintle Valve
A torsion spring
A one-way clutch
