AP GN Basic Electricity

The working voltage of a capacitor in an AC circuit should be

equal to the highest applied voltage.
at least 20 percent greater than that highest applied voltage.
at least 50 percent greater than the highest applied voltage.

The term that describes the combined resistive forces in an AC circuit is

resistance
reactance
impedance

What is the opposition to the flow of AC produced by an electromagnetic field (EMF) with generated back voltage called?

Inductive reactance.
Capacitive reactance.
Mutual inductance.

Electrostatic fields are also known as

dielectric fields.
electrostatic fields.
static fields.

The basis for transformer operation in the use of alternating current is mutual

inductance.
capacitance.
reactance.

The opposition offered by a coil to the flow of alternating current (ignoring resistance) is called

impedance.
reluctance.
inductive reactance.

What factors strengthen a coil inductor?

Limiting and separating the coils.
Adding and separating the coils.
Adding coils close together.

An increase in which of the following factors will cause an increase in the inductive reactance of a circuit?

Inductance and frequency.
Resistance and voltage.
Resistance and capacitive reactance.

Refer to Figure 1. When different rated capacitors are connected in series in a circuit, the total capacitance is

less than the capacitance of the lowest rated capacitor.
greater than the capacitance of the highest rated capacitor.
equal to the sum of all the capacitances.

Capacitors are sometimes used in DC circuits to

counteract inductive reactance at specific locations.
smooth out slight pulsations in current/voltage.
assist in stepping voltage and current up and/or down.

In an AC circuit, the effective voltage is

equal to the maximum instantaneous voltage.
greater than the maximum instantaneous voltage.
less than the maximum instantaneous voltage.

The amount of electricity a capacitor can store is directly proportional to the

distance between the plates and inversely proportional to the plate area.
plate area and is not affected by the distance between the plates.
plate area and inversely proportional to the distance between the plates.

Refer to Figure 2. What is the total capacitance of a certain circuit containing three capacitors with capacitances of .02 microfarad, .05 microfarad, and .10 microfarad, respectively?

.170 µF
0.125 pF.
.0125 µF

What is the total capacitance of a circuit containing three capacitors in parallel with capacitances of .02 microfarad, .05 microfarad, and .10 microfarad, respectively?

.170 µF
0.125 µF
.0125 µF

Convert farads to microfarads by

multiplying farads by 10 to the power of 6.
multiplying picofarads by 10 to the power of 6.
multiplying microfarads by 10 to the power of 6.

Convert farads to picofarads by

multiplying farads by 10 to the power of 12.
multiplying microfarads by 10 to the power of -12.
multiplying picofarads by 10 to the power of 12.

Unless otherwise specified, any values given for current or voltage in an AC circuit are assumed to be

instantaneous values.
effective values.
maximum values.

When different rated capacitors are connected in parallel in a circuit, the total capacitance is

(Note: C_{T =}C₁ + C₂ + C₃….)

less than the capacitance of the lowest rated capacitor.
equal to the capacitance of the highest rated capacitor.
equal to the sum of all the capacitances.

When inductors are connected in series in a circuit, the total inductance (where the magnetic fields of each inductor do not affect the others) is

(Note: L_T = L₁ + L₂ + L₃….)

less than the inductance of the lowest rated inductor.
equal to the inductance of the highest rated indutor.
equal to the sum of the individual inductances.

Refer to Figure 3. When more than two inductors of different inductances are connected in parallel in a circuit, the total inductance is

less than the inductance of the lowest rated inductor.
equal to the inductance of the highest rated inductor.
equal to the sum of the individual inductances.

What is the total capacitance of a certain circuit containing three capacitors with capacitances of .25 microfarad, .03 microfarad, and .12 microfarad, respectively?

(Note: C_T = C₁ + C₂+ C₃)

.4 µF
.04 pF
.04 µF

Which requires the most electrical power during operation?

A 12-volt motor requiring 8 amperes.
Four 30-watt lamps in a 12-volt parallel circuit.
Two lights requiring 3 amperes each in a 24-volt parallel system.

How much power must a 24-volt generator furnish to a system which contains the following loads?

One motor (75 percent efficient) with a rating of 1/5 hp
Three position lights with a rating of 20 watts each
One heating element with a rating of 5 amp
One anti-collision light with a rating of 3 amp
(Note 1 horsepower = 746 watts)

402 watts
385 watts
450 watts

A 12-volt electric motor has 1,000 watts input and 1 horsepower output. Maintaining the same efficiency, how much input power will a 24-volt, 1 horsepower electric motor require?

1,000 watts
2,000 watts
500 watts

How many amperes will a 28-volt generator be required to supply to a circuit containing five lamps in parallel, three of which have a resistance of 6 ohms each and two of which have a resistance of 5 ohms each?

1.11 amperes
1 ampere
1 ampere
25.23 amperes

A 24-volt, 1 horsepower DC electric motor that is 80% efficient requires 932.5 watts. How much power will a 12-volt, 1 horsepower DC electric motor that is 75% efficient require?

932.5 watts
1,305.5 watts
994.5 watts

The potential difference between two conductors which are insulated from each other is measured in

volts
amperes
coulombs

Which effect does not apply to the movement of electrons flowing in a conductor?

Magnetic energy
Thermal energy
Static energy

A 24-volt source is required to furnish 48 watts to a parallel circuit consisting of four resistors of equal value. What is the voltage drop across each resistor?

12 volts
6 volts
24 volts

When calculating power in a reactive or inductive AC circuit, the true power is

more than the apparent power.
less than the apparent power in a reactive circuit and more than the apparent power in an inductive circuit.
less than the apparent power.

Refer to Figure 4. How much power is being furnished to the circuit?

575 watts
2,875 watts
2,645 watts

Refer to Figure 5. What is the impedance of an AC-series circuit consisting of an inductor with a reactance of 10 ohms, a capacitor with a reactance of 4 ohms, and a resistor with a resistance of 8 ohms?

22 ohms
5.29 ohms
10 ohms

Refer to Figure 6. If resistor R5 is disconnected at the junction of R4 and R3 as shown, what will the ohm-meter read?

2.76 ohms
3 ohms
12 ohms

Refer to Figure 7. If resistor R3 is disconnected at terminal D, what will the ohmmeter read?

infinite resistance
10 ohms
20 ohms

Refer to Figure 8. With an ohmmeter connected into the circuit as shown, what will the ohmmeter read?

20 ohms
Infinite resistance
10 ohms

Refer to Figure 9. How many instruments (voltmeters and ammeters) are installed correctly?

Three
One
Two

The correct way to connect a test voltmeter in a circuit is:

in series with a unit.
between the source voltage and the load.
in parallel with a unit.

What will a voltmeter read if properly connected across a closed switch in a circuit with electrical power on?

Voltage drop in the component(s) the switch is connected to.
System voltage.
Zero voltage.

What does the letter Q symbolize when measuring electrical charge?

Farad
Electron
Coulomb.

Which term means .001 ampere?

Microampere
Kiloampere
Milliampere

A cabin entry light of 10 watts and a dome light of 20 watts are connected in parallel to a 30-volt source. If the voltage across the 10-watt light is measured, it will be

equal to the voltage across the 20-watt light.
half the voltage across the 20-watt light.
one-third of the input voltage.

A 14-ohm resistor is to be installed in a series circuit carrying .05 ampere. How much power will the resistor be required to dissipate?

At least .70 milliwatt.
At least .35 millwatts.
Less then .035 watt.

.002 kV equals

20 volts
2.0 volts
.2 volt

Refer to Figure 10. What is the measured voltage of the series-parallel circuit between terminals A and B?

1.5 volts
3.0 volts
4.5 volts

Refer to Figure 64. A 24-volt source is required to furnish 48 watts to a parallel circuit consisting of two resistors of equal value. What is the value of each resistor?

24 ohms
12 ohms
6 ohms

Which requires the most electrical power? (Note: 1 horsepower is 746 watts)

A 15-horsepower, 24-olt motor which is 75% efficient.
Four 30-watt lamps arranged in a 12-volt parallel circuit.
A 24-volt anticollision light circuit consisting of two light assemblies which require 3 amperes each during operation.

What unit is used to express electrical power?

Volt
Watt
Ampere

What is the basic unit of electrical quantity?

Electromotive force.
Ampere.
Coulomb.

What is the operating resistance of a 30-watt light bulb designed for a 28-volt system?

1.07 ohms.
26 ohms.
0.93 ohm.

When referencing resistance in a parallel DC circuit, which of the following statements is true?

The current is equal in all portions of the circuit.
The total current is equal to the sum of the currents through the individual branches of the circuit.
The current in amperes can be found by dividing the source voltage in volts by the sum of the resistors in ohms.

Which of the following is commonly used as a rectifier in electrical circuits?

Diodes and anodes.
Diodes and cathodes.
Diodes.

Diodes are used in electrical power supply circuits primarily as

switches.
rectifiers.
relays.

Transfer of electric energy from one circuit to another without the aid of electrical connections

is called induction.
is called capacitance.
can cause extensive arcing and heat, and as a result is practical for use only with low voltages/amperages.

If three resistors of 3 ohms, 5 ohms, and 22 ohms are connected in series in a 28-volt circuit, how much current will flow through the 3-ohm resistor?

9.3 amperes.
1.35 amperes.
0.93 amperes.

A circuit has an applied voltage of 30 watts and a load consisting of a 10-ohm resistor in series with a 20-ohm resistor. What is the voltage drop across the 10-ohm resistor?

10 volts.
20 volts.
30 volts.

Refer to Figure 11. Find the total current flowing in the wire between points C and D.

6.0 amperes
2.4 amperes
3.0 amperes

Refer to Figure 11. Find the voltage across the 8-ohm resistor.

8 volts.
20.4 volts.
24 volts.

In a parallel circuit with four 6-ohm resistors across a 24-volt battery, what is the total voltage across resistor-three (VR3) in the circuit?

6 volts
18 volts
24 volts

If each cell, connected in series, equals 2 volts, how would a 12-cell lead acid battery be rated?

24 volts
12 volts
6 volts

Refer to Figure 12. Find the total resistance of the circuit.

16 ohms
2.6 ohms
21.2 ohms

Which is correct in reference to electrical resistance?

Two electrical devices will have the same combined resistance if they are connected in series as they will have if connected in parallel.
If one of three bulbs in a parallel lightning circuit is removed, the total resistance of the circuit will become greater.
An electrical device that has a high resistance will use more power than one with a low resistance with the same applied charge.

What happens to the current in a voltage step-up transformer with a ratio of 1 to 4?

The current is stepped down by a 1 to 4 ratio.
The current is stepped up by a 1 to 4 ratio.
The current does not change.

Refer to Figure 13. Determine the total current flow in the circuit.

0.2 ampere
1.4 amperes
0.8 amperes

In a parallel circuit with three 6-ohm resistors across a 12-volt battery, what is the total current (l_t) value in the circuit?

2 amps
6 amps
12 amps

Refer to Figure 14. The total resistance of the circuit is

25 ohms
35 ohms
17 ohms

Which of these will cause the resistance of a conductor to decrease?

Decrease the length or the cross-sectional area.
Decrease the length or increase the cross-sectional area.
Increase the length or decrease the cross-sectional area.

Through which material will magnetic lines of force pass the most readily?

Copper
Iron
Aluminum

Refer to Figure 64. A 48-volt source is required to furnish 192 watts to a parallel circuit consisting of three resistors of equal value. What is the value of each resistor?

36 ohms
4 ohms
12 ohms

Which is correct concerning a parallel circuit?

Total resistance will be smaller than the smallest resistor.
Total resistance will decrease when one of the resistances is removed.
Total voltage drop is the same as the total resistance.

The voltage drop in a circuit of known resistance is dependent on

the voltage of the circuit.
only the resistance of the conductor and does not change with a change in either voltage or amperage.
the amperage of the circuit.

A thermal switch, or thermal protector, as used in an electric motor, is designed to

close the integral fan circuit to allow cooling of the motor.
open the circuit in order to allow cooling of the motor.
reroute the circuit to ground.

Refer to Figure 15. With the landing gear retracted, the red indicator light will not come on if an open occurs in wire

19
17
7

Refer to Figure 15. Wire 7 is used to

close the PUSH-TO-TEST circuit.
open the UP indicator light circuit when the landing gear is retracked.
close the UP indicator light circuit when the landing gear is retracted.

Refer to Figure 15. When the landing gear is down, the green light will not come on if an open occurs in wire

7
6
17

Refer to Figure 16. What will be the effect if the PCO relay fails to operate when the left-hand tank is selected?

The fuel pressure crossfeed valve will not open.
The fuel tank crossfeed valve open light will illuminate.
The fuel pressure crossfeed valve open light will not illuminate.

Refer to Figure 16. The TCO relay will operate if 24-volts DC is applied to the bus and the fuel tank selector is in the

right-hand tank position.
crossfeed position.
left-hand tank position.

Refer to Figure 16. With power to the bus and the fuel selector switched to the right-hand tank, how many relays in the system are operating?

Three
Two
Four

Refer to Figure 16. When electrical power is applied to the bus, which relays are energized?

PCC and TCC
TCC and TCO
PCO and PCC

Refer to Figure 16. Energize the circuit with the fuel tank selector switch selected to the left-hand position. Using the schematic, identify the switches that will change position.

5, 9, 10, 11, 12, 13, and 15.
3, 5, 6, 7, 11, and 13.
5, 6, 11, 12, 13, 15, and 16.

Refer to Figure 17. Which of the components is a potentiometer?

5
3
11

Refer to Figure 17. The electrical symbol represented at number 5 is a variable

inductor.
resistor.
capacitor.

Refer to Figure 18. When the landing gear is up and the throttles are retarded, the warning horn will not sound it an open occurs in wire

4
2
9

Refer to Figure 18. The control valve switch must be placed in the neutral position when the landing gear is down to

permit the test circuit to operate.
prevent the warning horn from sounding when the throttles are closed.
remove the ground from the green light.

Refer to Figure 19. Under which condition will a ground be provided for the warning horn through both gear switches when the throttles are closed?

Right gear up and left gear down.
Both gears up and the control valve out of neutral.
Left gear up and right gear down.

Refer to Figure 19. When the throttles are retarded with only the right gear down, the warning horn will not sound if an open occurs in wire

5
13
6

Refer to Figure 19. When the landing gears are up and the throttles are retarded, the warning horn will not sound if an open occurs in wire

5
7
6

When referring to an electrical circuit diagram, what point is considered to be at zero voltage?

The circuit breaker.
The switch.
The ground reference.

What is the purpose of the ground symbol used in electrical circuit diagrams?

To show that there is common bus for connection of the source of electrical energy to the load.
To show the source of electrical energy for the load.
To show that there is a return path for the current between the source of electrical energy and the load.

Refer to Figure 20. Troubleshooting an open circuit with a voltmeter as shown in this circuit will

permit current to flow and illuminate the lamp.
create a low resistance path and the current flow will be greater than normal
permit the battery voltage to appear on the voltmeter.

Refer to Figure 21. Which symbol represents a variable resistor?

2
1
3

In a P-N-P transistor application, the solid-state device is turned on when the

base is negative with respect to the emitter.
base is positive with respect to the emitter.
emitter is negative with respect to the base.

In an N-P-N transistor application, the solid-state device is turned on when the

emitter is positive with respect to the base.
base is negative with respect to the emitter.
base is positive with respect to the emitter.

Typical application for zener diodes is as

full wave rectifiers.
half wave rectifiers.
voltage regulators.

Refer to Figure 22. Which illustration is correct concerning bias application and current (positive charge) flow?

1
2
3

Forward biasing of a solid-state device will cause the device to

conduct via zener breakdown.
conduct.
turn off.

Refer to Figure 23. If an open occurs at R1, the light

cannot be turned on.
will not be affected.
cannot be turned off.

Refer to Figure 23. If R2 sticks in the up position, the light will

be on full bright.
be very dim.
not illuminate.

Refer to Figure 24. Which statement concerning the depicted logic gate is true?

Any input being 1 will produce a 0 output.
Any input being 1 will produce a 1 ioutput.
All inputs must be 1 to produce a 1 output.

Refer to Figure 25. In a functional and operating circuit, the depicted logic gate’s output will be 0

only when all inputs are 0.
when all inputs are 1.
when one or more inputs are 0.

Refer to Figure 26. Which of the logic gate output conditions is correct with respect to the given inputs?

1
2
3

Which of the following topic gates will provide an active high out only when all inputs are different?

XNOR
NAND
XOR

At lead-acid battery with 12 cells connected in series (no-load voltage = 2.1 volts per cell) furnishes 10 amperes to a load of 2-ohms resistance. The internal resistance of the battery in this instance is

0.52 ohm
2.52 ohms
5.0 ohms

If electrolyte from a lead-acid battery is spilled in the battery compartment, which procedure should be followed?

Apply boric acid solution to the affected area followed by a water rinse.
Rinse the affected area thoroughly with clear water.
Apply sodium bicarbonate solution to the affected area followed by a water rinse.

Which statement regarding the hydrometer reading of a lead-acid storage battery electrolyte is true?

The hydrometer reading does not require a temperature correction if the electrolyte temperature is 80 degrees F.
A specific gravity connection should be added to the hydrometer reading if the electrolyte temperature is below 59 degrees F.
The hydrometer reading will give a true indication of the capacity of the battery regardless of the electrolyte temperature.

A fully charged lead-acid battery will not freeze until extremely low temperatures are reached because

the acid is in the plates, thereby increasing the specific gravity of the solution.
most of the acid is in the solution.
increased internal resistance generates sufficient heat to prevent freezing.

What determines the amount of current which will flow through a battery while it is being charged by a constant voltage source?

The total plate area of the battery.
The state-of-charge of the battery.
The ampere-hour capacity of the battery.

Which of the following statements is/are generally true regarding the charging of several aircraft batteries together?

Batteries of different voltages (but similar capacities) can be connected in series with each other across the charger, and charged using the constant current method.
Batteries of different ampere-hour capacity and same voltage can be connected in parallel with each other across the charger, and charged using the constant voltage method.
Batteries of the same voltage and same ampere-hour capacity must be connected in series with each other across the charger, and charged using the constant current method.

3
2 and 3.
1 and 2.

The method used to rapidly charge a nickel-cadmium battery utilizes

constant current and constant voltage.
constant current and varying voltage.
constant voltage and varying current.

The purpose of providing a space underneath the plates in a lead acid batter’s cell container is to

prevent sediment buildup from contacting the plates and causing a short circuit.
allow for convection of the electrolyte in order to provide for cooling of the plates.
ensure that the electrolyte quantity ratio to the number of plates and plate area is adequate.

Which condition is an indication of improperly torqued cell link connections of a nickel-cadmium battery?

Light spewing at the cell caps.
Toxic and corrosive deposits of potassium carbonate crystals.
Heat or burn marks on the hardware.

The presence of any small amount of potassium carbonate deposits on the top of nickel-cadmium battery cells in service is an indication of

normal operation.
excessive gassing.
plate sulfation.

What is the likely result, if any, of servicing and charging nickel-cadmium and lead-acid batteries together in the same service area?

The electrolytes in each battery are the same, so there are no significant differences.
The nickel-cadmium would not be affected, but the lead-acid battery could become contaminated.
Contamination of both types of batteries would occur.

Which of the following best describes the operating principal in a nickel-cadmium battery installed in an aircraft?

At full charge, the electrolyte will be at its lowest level and should be filled.
To completely charge a nickel-cadmium battery, some gassing must take place, thus, some water will be used.
When positive plates slowly give up oxygen, which is required by the negative plates, the battery is charging.

The electrolyte of a nickel-cadmium battery is the lowest when the battery is

being charged.
in a discharged condition.
under a heavy load condition.

The electrolyte of a nickel-cadmium battery is the highest when the battery is

in a fully charged condition.
in a discharged condition.
under a no-load condition.

The end-of-charge voltage of a 19-cell nicked-cadmium battery, measured while still on charge

must be 1.2 to 1.3 volts per cell.
must be 1.4 volts per cell.
depends upon its temperature and the method used for charging.

During discharge, nicked-cadmium batteries will show a lower liquid level than when at full charge because

a chemical action causes the electrolyte to evaporate through the vents.
current leakage from individual cells causes a rise in temperature.
the electrolyte becomes absorbed into the plates.

How can the state-of-charge of a nickel-cadmium battery be determined?

By measuring the specific gravity of the electrolyte.
By a measured discharge.
By the level of the electrolyte.

What may result if water is added to a nickel-cadmium battery when it is not fully charged?

Excessive electrolyte dilution.
Excessive spewing is likely to occur during the charging cycle.
No adverse affects since water may be added anytime.

In nickel-cadmium batteries, a rise in cell temperature

causes an increase in internal resistance.
causes an decrease in internal resistance.
increases cell voltage.

Which of the following best describes the contributing factors to thermal runway in a nickel-cadmium battery installed in an aircraft?

High internal resistance intensified by high cell temperatures and a high current discharge/charge rate in a constant potential (voltage) charging system.
Low internal resistance intensified by high cell temperatures and a high voltage discharge/charge rate in a constant current charging system.
Low internal resistance intensified by high cell temperatures and a high current discharge/charge rate in a constant potential (voltage) charging system.

When a charging current is applied to a nickel-cadmium battery, the cells emit gas

toward the end of the charging cycle.
throughout the charging cycle.
especially if the electrolyte level is high.

AP GN Basic Electricity

Jon K

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