Automotive Electronics Practice Test

When charging a maintenance-free (lead-calcium) battery, _____. The initial charging rate should be about 35 amperes for 30 minutes The battery may not accept a charge for several hours, yet may still be a good (serviceable) battery The battery temperature should not exceed 125°F (hot to the touch) All of the above are correct

All of the above are correct

Mini-fuses are used for which of these reasons? Save space Carry a smaller current Carry a larger current Cost less

Save space

When measuring the specific gravity of the electrolyte, the maximum allowable difference between the highest and lowest hydrometer reading is _____. 0.010 0.020 0.050 0.50

0.050

If a 12 volt battery is connected to a series circuit with three resistors of 2 ohms, 4 ohms, and 6 ohms, how much current will flow through the circuit? 1 ampere 2 amperes 3 amperes 4 amperes

1 ampere

A throttle position sensor waveform is going to be observed. At what setting should the volts per division be set to see the entire waveform from 0 to 5 volts? 0.5 V/division 1.0 V/division 2.0 V/division 5.0 V/division

1.0 V/division

Setting the time base to 50 ms per division will allow the technician to view a waveform how long in duration? 50 ms 200 ms 400 ms 500 ms

500 ms

Maxi fuses are rated up to ________ amperes or more. 80 60 40 10

80

What battery rating is tested at 32°F (0°C)? Cold-cranking amperes (CCA) Cranking amperes (CA) Reserve capacity Battery voltage test

Cranking amperes (CA)

Which statements are true about wire, terminals, and connectors? Wire is called a lead, and the metal end is a connector. A connector is usually a plastic piece where terminals lock in. A lead and a terminal are the same thing. Both a and c are correct

A connector is usually a plastic piece where terminals lock in.

Wire repairs on wires exposed to the elements, require which type of these repair types? Wire nuts and electrical tape Rosin-core solder and electrical tape Crimp-and-seal connectors Butt connectors

Crimp-and-seal connectors

Technician A says a terminal is the metal end of a wire and the connector is the plastic housing for the. Technician B says a Maxi fuse is NOT a circuit protection device. Who is right? A only B only Both A and B Neither A nor B

A only

The positive battery plate is _____. Lead dioxide Brown in color Sometimes called lead peroxide All of the above

All of the above

Fuses are rated by which of these terms? Voltage Current Power Resistance

Current

Technician A says the fuse rating should be 50% of the maximum current for the circuit. Technician B says fuse rating should be higher than the normal current for the circuit. Who is right? A only B only Both A and B Neither A nor B

B only

As additional branches are added to a a parallel circuit, total circuit resistance ________. Remains the same Decreases Increases None of the above

Decreases

Two light bulbs are wired in series and one bulb burns out (opens.) Technician A says that the other bulb will work. Technician B says that the current will increase in the circuit because one electrical load (resistance) is no longer operating. Which technician is correct? Technician A Technician B Both Technicians A and B Neither Technician A nor B

Neither

The higher the American wire gauge (AWG) number, which of these happens? Thicker the insulation Smaller the wire More strands per foot Larger the wire

Smaller the wire

All brake lights are dimmer than normal. Technician A says that bad bulbs could be the cause. Technician B says that high resistance in the brake switch could be the cause. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician B only

Four resistors are connected to a 12 volt battery in series. The values of the resistors are 10 ohms, 100 ohms, 330 ohms, and 470 ohms. Technician A says that the greatest voltage drop will occur across the 10 ohm resistor. Technician B says that the greatest voltage drop will occur across the 470 ohm resistor. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician B only

When jump starting, _____. The last connection should be the positive post of the dead battery The last connection should be the engine block of the dead vehicle The generator (alternator) must be disconnected on both vehicles Both a and c are correct

The last connection should be the engine block of the dead vehicle

The faster a starter motor rotates _____. The more current it draws from the battery The less CEMF is generated The less current it draws from the battery The greater the amount of torque produced

The less current it draws from the battery

If one branch of a parallel circuit loses continuity, the other branches will still each receive source voltage and ground. True False

True

Which of these facts is true regarding circuit breakers? Less expensive than fuses Must be replaced after excess current flow Used for frequent temporary overloads Made of a single metal strip

Used for frequent temporary overloads

Kirchhoff's law states that the voltage around a closed circuit is equal to the sum of the ________ across all the loads. Voltage drops Resistances Both A & B Neither A nor B

Voltage drops

Two technicians are discussing fuse testing. Technician A says that a test light should light on both test points of the fuse if it is okay. Technician B says the fuse is defective if a test light only lights on one side of the fuse. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Both Technicians A and B

Many ground straps are uninsulated and braided because _____. They are more flexible to allow movement of the engine without breaking the wire They are less expensive than conventional wire They help dampen radio-frequency interference (RFI) Both a and c are correct

Both a and c are correct

The type of solder that should be used for electrical work is _____. Rosin core Acid core 60/40 with no flux 50/50 with acid paste flux

Rosin core

If a wire repair, such as that made under the hood or under the vehicle, is exposed to the elements, which type of repair should be used? Wire nuts and electrical tape Solder and adhesive-lined heat shrink or crimp-and-seal connectors Butt connectors Rosin-core solder and electrical tape

Solder and adhesive-lined heat shrink or crimp-and-seal connectors

A charge indicator (eye) operates by showing green or red when the battery is charged and dark if the battery is discharged. This charge indicator detects _____. Battery voltage Specific gravity Electrolyte water pH Internal resistance of the cells

Specific gravity

Two technicians are discussing the DC coupling setting on a DSO. Technician A says that the position allows both the DC and AC signals of the waveform to be displayed. Technician B says that this setting allows just the DC part of the waveform to be displayed. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician A only

A 6-cylinder engine uses six fuel injectors connected electrically in two groups of three injectors in parallel. What would be the resistance if the three 12 ohm injectors were connected in parallel? 36 ohms 12 ohms 4 ohms 3 ohms

4 ohms

What makes a battery "low maintenance" or "maintenance free"? Alloy is used to construct the grids. The plates are constructed of different metals. The electrolyte is hydrochloric acid solution. The battery plates are smaller, making more room for additional electrolytes

Alloy is used to construct the grids.

When load testing a battery, which battery rating is usually used to determine how much load to apply to the battery? CA RC MCA CCA

CCA

Which battery rating is tested at 0°F (-18°C)? Cold-cranking amperes (CCA) Cranking amperes (CA) Reserve capacity Battery voltage test

Cold-cranking amperes (CCA)

The voltage for each branch of a parallel circuit is ________. Reduced by the resistance of loads in each branch Equal Increased by the resistance of loads in each branch None of the above

Equal

What gases are released from a battery when it is being charged? Oxygen Hydrogen Nitrogen and oxygen Hydrogen and oxygen

Hydrogen and oxygen

If the resistance and the voltage are known, what is the formula for finding the current (amperes)? I = E x R E = I x R R = E x I I = E / R

I = E / R

The amperage in a series circuit ________. Is always less returning than leaving the battery. Is the same anywhere in the circuit. Is high at the beginning of the circuit and decreases as the current flows through the resistance. Varies in the circuit due to the different resistances.

Is the same anywhere in the circuit.

Two technicians are discussing fuse testing. Technician A says that a test light should only light on one side of the fuse if it is OK. Technician B says the fuse must be tested using a Gauss Gauge. Who is right? A only B only Both A and B Neither A nor B

Neither A nor B

Which battery rating is expressed in minutes? Cold-cranking amperes (CCA) Cranking amperes (CA) Reserve capacity Battery voltage test

Reserve capacity

The sum of the voltage drops in a series circuit equals the ________. Resistance Source voltage Wattage Amperage

Source voltage

Technician A says an analog scope can store the waveform for viewing later. Technician B says that the trigger level has to be set on most scopes to be able to view a changing waveform. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician B only

Technician A says that a defective solenoid can cause a starter whine. Technician B says that a defective starter drive can cause a starter whining noise. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician B only

All batteries should be in a secure bracket that is bolted to the vehicle to prevent physical damage to the battery. True False

True

Resistance Total in series-parallel is found by P1*P2/P1+P2 to find total resistance in parallel, then adding that to the series resistance. True False

True

All of these are used for circuit protection, EXCEPT Bus bar Maxi-Fuse Circuit breaker Fuse

Bus bar

Which statement is true about fuse ratings? The fuse rating is measured in volts. The fuse rating should be higher than the normal current for the circuit. A replacement fuse rating should be the same as the original fuse. Both b and c are correct

Both b and c are correct

More electrical current will tend to flow through the branch of a parallel circuit with ________ resistance. Infinite Lowest Highest None of the Above

Lowest

Technician A says Metric wire is sized in cubic millimeters (mm3) and the higher the number, the larger the wire. Technician B says the higher the AWG gauge size number, the larger the wire. Who is right? A only B only Both A and B Neither A nor B

Neither A nor B

Metric wire size is measured in units of _____. Meters Cubic centimeters Square millimeters Cubic millimeters

Square millimeters

What unit contains a hold-in winding and a pull-in winding? Field coil Starter solenoid Armature Ignition switch

Starter solenoid

Two identical bulbs are connected to a 12 volt battery in parallel. The voltage drop across the first bulb is 12 volts as measured with a voltmeter. What is the voltage drop across the other bulb? 0 volt 1 volt 6 volts 12 volts

12 volts

Normal cranking speed of the engine is about _____. 2000 RPM 1500 RPM 1000 RPM 200 RPM

200 RPM

Oscilloscopes use what type of lead connector? Banana plugs Double banana plugs Single conductor plugs BNC

BNC

Many vehicle manufacturers recommend that a special electrical connector be installed between the battery and the battery cable when testing for _____. Battery drain (parasitic drain) Specific gravity Battery voltage Battery charge rate

Battery drain (parasitic drain)

The neutral safety switch is located _____. Between the starter solenoid and the starter motor Inside the ignition switch itself Between the ignition switch and the starter solenoid In the battery cable between the battery and the starter solenoid

Between the ignition switch and the starter solenoid

A fully charged 12 volt battery should indicate _____. 12.6 volts or higher A specific gravity of 1.265 or higher 12 volts Both a and b

Both a and b

A vehicle has four taillight bulbs all connected in parallel. If one bulb burns out (opens), the current flow in the circuit _____. Increases and the other bulbs get brighter Decreases because only three bulbs are operating Remains the same because all the bulbs are wired in parallel Drops to zero and the other three bulbs go out

Decreases because only three bulbs are operating

Permanent magnets are commonly used for what part of the starter? Armature Solenoid Field coils Commutator

Field coils

The brushes are used to transfer electrical power between _____. Field coils and the armature The commutator segments The solenoid and the field coils The armature and the solenoid

Field coils and the armature

The plastic color of the blade fuses indicate which of these? Size of the blade Size of the wire Maximum current flow Maximum voltage

Maximum current flow

The higher the resistance of a load in a series circuit, the __________ the voltage drops across that load. Less Equal More None of the above

More

Voltage signals (waveforms) that do not go below zero are called _____. AC signals Pulse trains DC signals DC coupled signal

Pulse trains

A series circuit has three resistors of 4 ohms each. The voltage drop across each resistor is 4 volts. Technician A says that the source voltage is 12 volts. Technician B says that the total resistance is 18 ohms. Which technician is correct? Tech A Tech B Both Neither

Tech A

In a series circuit, total circuit resistance is equal to the ________ of the resistance of all loads in the circuit. Sum Dividend Difference None of the Above

Sum

A vehicle has four parking lights all connected in parallel and one of the bulbs burns out. Technician A says that this could cause the parking light fuse to blow (open). Technician B says that it would decrease the current in the circuit. Which technician is correct? Tech A Tech B Both Neither

Tech B

A battery high-rate discharge (load capacity) test is being performed on a 12 volt battery. Technician A says that a good battery should have a voltage reading of higher than 9.6 volts while under load at the end of the 15 second test. Technician B says that the battery should be discharged (loaded) to twice its CCA rating. Which technician is correct? Technician A only Technician B only Both Technician's A and B Neither Technician A nor B

Technician A only

A series circuit has two 10 ohm bulbs. A third 10 ohm bulb is added in series. Technician A says that the three bulbs will be dimmer than when only two bulbs were in the circuit. Technician B says that the current in the circuit will increase. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician A only

A starter motor rotates about _____ times faster than the engine. 18 10 5 2

18

Battery cables are the largest wires used in the automotive electrical system. The cables are what gauge wire? 12 2 14 6

2

Three resistors are connected in parallel to a 12 volt battery. The total current flow from the battery is 12 amperes. The first resistor is 3 ohms and the second resistor is 6 ohms. What is the value of the third resistor? 1 Ω 2 Ω 3 Ω 4 Ω

2 ohms

Calculate the total resistance and current in a 12-volt parallel circuit with three resistors of 4 ohms, 8 ohms, and 16 ohms, using any one of the five methods (calculator suggested). What are the total resistance and current? 140 ohms (18 amps) 4 ohms (3.0 amps) 2.3 ohms (5.3 amps) 22 ohms (0.4 amps)

2.3 ohms

Normal battery drain (parasitic drain) with a vehicle with many computer and electronic circuits is _____. 20 to 30 milliamperes 2 to 3 amperes 150 to 300 milliamperes None of the above

20 to 30 milliamperes

Three resistors are connected to a 12 volt battery in parallel. The current flow through each resistor is 4 amperes. What is the value of the resistors? 1 ohm 2 ohms 3 ohms 4 ohms

3 ohms

Technician A says that electronic calculators have a memory function that can be used to calculate resistance, current, and voltage values for a parallel circuit. Technician B says that components of a series-parallel circuit are separated to simplify calculations. Which technician is correct? Tech A Tech B Both Neither

Both

A series circuit has three resistors of 6 ohms each. The voltage drop across each resistor is 4 volts. Technician A says that the source voltage is 12 volts. Technician B says that the total resistance is 18 ohms. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Both Technicians A and B

Technician A says that the sum of the voltage drops in a series circuit should equal the source voltage. Technician B says that the current (amperes) varies depending on the value of the resistance in a series circuit. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Both Technicians A and B

What causes a fuse to blow? A decrease in circuit resistance An increase in the current flow through the circuit A sudden decrease in current flow through the circuit Both a and b

Both a and b

A digital meter that can show waveforms is called a _____. DVOM DMM GMM DSO

GMM

An oscilloscope display is called a _____. Grid Graticule Division Box

Graticule

Cycles per second are expressed in _____. Hertz Duty cycle Pulse width Slope

Hertz

Two bulbs are connected to a 12 volt battery in parallel. Another bulb is added in parallel. Technician A says that the third bulb will be dimmer than the other two bulbs due to reduced current flow through the filament of the bulb. Technician B says that the amount of current flowing from the battery will decrease due to the extra load. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Neither Technician A nor B

When a battery becomes completely discharged, both positive and negative plates become _____ and the electrolyte becomes _____. H2SO4 /Pb PbSO4 /H2O PbO2 /H2SO4 PbSO4 /H2SO4

PbSO4 /H2O

Series-wound electric motors _____. Produce electrical power Produce maximum power at 0 RPM Produce maximum power at high RPM Use a shunt coil

Produce maximum power at 0 RPM

A signal showing the voltage of a battery displayed on an analog oscilloscope is being discussed. Technician A says that the display will show one horizontal line above the zero line. Technician B says that the display will show a line sloping upward from zero to the battery voltage level. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician A only

A technician is performing a wire repair on a circuit that uses 18 gauge wire. The parts department does not have 18 gauge wire but it does have 16 gauge wire and 20 gauge wire. Technician A says to use the 16 gauge wire. Technician B says to use the 20 gauge wire. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician A only

Technician A says that distilled or clean drinking water should be added to a battery when the electrolyte level is low. Technician B says that fresh electrolyte (solution of acid and water) should be added. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician A only

Half of the dash is dark. Technician A says that a defective dash light dimmer can be the cause because it is in series with the bulbs that are in parallel. Technician B says that one or more bulbs could be defective. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician B only

Three light bulbs are wired in series. A fourth bulb is connected to the circuit in series. Technician A says that the total voltage drop will increase. Technician B says that the current (amperes) will decrease. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician B only

Two bulbs are connected in parallel to a 12 volt battery. One bulb has a resistance of 6 ohms and the other bulb has a resistance of 2 ohms. Technician A says that only the 2 ohm bulb will light because all of the current will flow through the path with the least resistance and no current will flow through the 6 ohm bulb. Technician B says that the 6 ohm bulb will be dimmer than the 2 ohm bulb. Which technician is correct? Technician A only Technician B only Both Technicians A and B Neither Technician A nor B

Technician B only

Starter motors operate on the principle that _____. The field coils rotate in the opposite direction from the armature Opposite magnetic poles repel Like magnetic poles repel The armature rotates from a strong magnetic field toward a weaker magnetic field

The armature rotates from a strong magnetic field toward a weaker magnetic field

Deep cycling means _____. Overcharging the battery Overfilling or underfilling the battery with water The battery is fully discharged and then recharged The battery is overfilled with acid (H2SO4)

The battery is fully discharged and then recharged

If an accessory such as an additional light is spliced into an existing circuit in parallel, what happens? The current increases in the circuit. The current decreases in the circuit. The voltage drops in the circuit. The resistance of the circuit increases

The current increases in the circuit.

A battery date code sticker indicates D6. What does this mean? The date it was shipped from the factory was December 2006. The date it was shipped from the factory was April 2006. The battery expires in December 2002. It was built the second day of the week (Tuesday).

The date it was shipped from the factory was April 2006.

The higher the AWG number, _____. The smaller the wire The larger the wire The thicker the insulation The more strands in the conductor core

The smaller the wire