Electrical Flashcards
To prevent the engine from driving the starter motor, if the starter switch is not released on starting. What is fitted?
A one way clutch.
The relative density of the electrolyte in a fully charged lead acid battery is approximately what?
1.280
An alternator rectifier is fitted with what?
A number of diodes
Where is the ‘lambda sensor’ usually located?
In the exhaust front pipe
What is a loose or dirty terminal likely to cause?
The engine not to start
When changing a faulty halogen head lamp bulb you must be careful not to what?
Not to touch the bulbs glass
After driving a diesel engined vehicle into the workshop, you try to turn it off but the engine keeps running a likely fault is?
Faulty fuel cut-off solenoid
The fault shown on the electrical diagram is?
A short circuit
With the meter connected as shown in the illustration, what voltage will the meter display?
6 volts
A loose alternator belt is likely to cause what?
A flat battery
Which of the meters is connected in series with the circuit components to get a reading?
Ammeter
In the circuit below, the pd measured across the 8 ohm resistor will be?
4 volts
A means of providing low current switching for a high current starter motor circuit is by the use of?
A solenoid
If you were to connect the leads of an ammeter directly to the positive and negative terminals of a battery, what you happen?
You would seriously damage the meter
The diagram shows two resistors in a circuit, the resistors are connected in?
Series
If a customer complains of the need to frequently replace bulbs and the lights are very bright, the likely fault is?
A defective voltage regulator
The diagram shows part of a lighting circuit. If the side beam and rear lamps and main beam lamps operate, but the dip beam lamps fail to operate, the likely cause is?
The dip switch is faulty
What will a high resistance in the battery earth lead connection cause the earth lead to do?
Get hot when starting the engine
By connecting a voltmeter across the battery terminals and observing the reading whilst cranking over the starter motor you can?
Calculate the volt drop
Before testing an electric component for the first time you should always what?
Check the test procedure in the workshop manual
The diagram shows part of a lighting circuit. What is the effect if the earth connection to the component labelled ‘A’ is broken?
The side and rear lamps operate normally but the dip and main beam lamps fail to operate
The unit of electrical power is?
Watt
A bad earth connection on a rear lamp may cause the light to?
Go dim
In a 12 volt lighting circuit 4 lamps are connected in parallel, each lamp is rated at 6 watt. The current used by this circuit is?
2 amp
To stop the starter motor being turned when the engine starts it is fitted with?
A one way clutch
What type of starter is shown in the picture?
Pre-engaged
A colleague suffers an electric shock when using an electric drill. Your first action is?
Switch off the power supply
What would be the voltage of a cell in a fully charged battery?
2.1 volts
An LED is a type of?
Light emitting diode
A thermistor is a type of?
Sensor that is temperature sensitive
What would be used to measure the specific gravity of a batteries electrolyte solution?
Hydrometer
Which of the following is a true statement regarding the requirements of the Vehicle Lighting Regulations?
Vehicle lights must be maintained in working order at any time
What would NOT cause an excessive voltage drop in a lighting circuit?
Light switch being left on
A relay is normally fitted to a vehicle’s headlamp circuit to?
Reduce the current flow through the lighting switch
Current flow in a circuit is measured using?
An ammeter
The alternator stator is found?
In the casing
To power a heavy duty 12 volt starter motor, you may need to connect two 12 volt batteries?
In parallel
In a vehicle alternator, the rectifier pack?
Converts AC to DC
To avoid damaging an ammeter you should only connect?
In series with circuit components
The light from a front fog light is dim. Which of the following is NOT a possible cause of the fault?
Open circuit supply cable
The starter switch is operated and the starter motor turns very slowly. What would NOT be a cause of the fault?
A defective roller clutch
What is the optimum charging voltage for a vehicle with a 12V electrical system?
14.4v
An ammeter is in series with a 12 volt lamp and shows a current flow of 2 amps. What is the power rating of the lamp?
24 Watt
The diagram shows two resistors R1 & R2. What is the reading on the ammeter labelled A2 and the voltmeter labelled V?
A2 = 6 Amps, V = 12 Volts
What is the equation for watts law?
P=I*V
What is the equation for ohms law?
V=I*R
An electrical cable is designated as 28/0.30, what does this mean?
It has 28 strands each with a diameter of 0.30mm.
An ohm meter?
Should not be used to test a battery.
When disconnecting a battery, the first terminal to be disconnected must always be?
The earth terminal.
When removing or repairing electronic communication systems or components it is advisable to?
Earth yourself to the car to discharge static electricity before starting to disconnect.
