Basic Electricity
An increase in which of the following factors will cause an increase in the inductive reactance of a circuit?
Inductive and frequency.
What is the opposition to the flow of AC produced by a magnetic field with generated back voltage (EMF) called?
Inductive reactance.
(Refer to Figure 18.) When the landing gears are up and the throttles are retarded, the warning horn will not sound if an open occurs in wire
No. 4.
What is the operating resistance of a 30-watt light bulb designed for a 28-volt system?
26 ohms.
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 uF.
(Refer to Figure 4.) How much power is being furnished to the circuit?
2,645 watts.
(Refer to Figure 2.) What is the total capacitance of a circuit containing three capacitors with capacitances of .02 microfarad, .05 microfarad, and .10 microfarad, respectively?
.0125 uF
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) = C(1) + C(2) + C(3))
.4 uF
A 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.
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?
0.93 amere.
(Refer to Figure 22.) Which illustration is correct concerning bias application and current (positive charge) flow?
1
Which of the following statements is/are generally true regarding the charging of several aircraft batteries together? 1. 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. 2. 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. 3. 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.
1 and 2.
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? (Note: 1 horsepower = 746 watts)
1,000 watts.
(Refer to Figure 13.) Determine the total current flow in the circuit.
1.4 ampers.
(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?
10 ohms.
(Refer to Figure 8.) With an ohmmeter connected into the circuit as shown, what will the ohmmeter read?
10 ohms.
A circuit has an applied voltage of 30 volts 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.
(Refer to Figure 14.) The total resistance of the circuit is
17 ohms.
(Refer to Figure 21.) Which symbol represents a variable resistor?
2
(Refer to Figure 26.) Which of the logic gate output conditions is correct with respect to the given inputs?
2
.002KV equals
2.0 volts
(Refer to Figure 12.) Find the total resistance of the circuit.
21.2 ohms.
(Refer to Figure 11.) Find the voltage across the 8-ohm resistor.
24 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? (Note: R(t) = E^2/P)
24 ohms.
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?
24 volts
If each cell, connected in series, equals 2 volts, how would a 12-cell lead acid battery be rated?
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?
24 volts.
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?
25.23 ampers.
(Refer to Figure 17.) Which of the components is a potentiometer?
3
(Refer to Figure 6.) If resistor R(5) is disconnected at the junction of R(4) and R(3) as shown, what will the ohmmeter read?
3 ohms.
Which of the following are commonly used as rectifiers in electrical circuits? 1. Anodes. 2. Cathodes. 3. Diodes
3.
(Refer to Figure 11.) Find the total current flowing in the wire between points C and D.
3.0 ampers.
(Refer to Figure 10.) What is the measured voltage of the series-parallel circuit between terminals A and B?
3.0 volts.
(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.
How much power must a 24-volt generator furnish to a system which contains the following loads? UNIT RATING One motor (75 percent efficient) 1/5 hp Three position lights 20 watts each One heating element 5 amp One anticollision light 3 amp (Note: 1 horsepower = 746 watts)
450 watts.
(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, 6, 11, 12, 13, 15, 16.
In a parallel circuit with three 6-ohms resistors across a 12-volt battery, what is the total current (It) value in the circuit?
6 amps.
A 1-horsepower, 24-volt dc electric motor that is 80 percent efficient requires 932.5 watts. How much power will a 1-horsepower, 12-volt dc electric motor that is 75 percent efficient require? (Note: 1 horsepower = 746 watts)
994.6 watts.
Which requires the most electrical power? (Note: 1 horsepower = 746 watts)
A 1/5 horsepower, 24-volt motor which is 75 percent efficient.
What factors strengthen a coil inductor?
Adding coils close together.
(Refer to Figure 24.) Which statement concerning the depicted logic gate is true?
Any input being 1 will produce a 1 output.
If electrolyte from a lead-acid battery is spilled in the battery compartment, which procedure should be followed?
Apply sodium bicarbonate solution to the affected area followed by a rinse of water.
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 35 milliwatts.
How can the state-of-charge of a nickel-cadmium battery be determined?
By the level of the electrolyte.
What does the letter Q symbolize when measuring electrical charge?
Coulomb.
What is the basic unit of electrical quantity?
Coulomb.
Which of these will cause the resistance of a conductor to decrease?
Decreases the length or increase the cross-sectional area.
Electrostatic fields are also known as
Dielectric fields
What may result if water is added to a nickel-cadmium battery when it is not fully charged?
Excessive spewing is likely to occur during the charging cycle.
Which condition is an indication of improperly torqued cell link connections of a nickel-cadmium battery?
Heat or burn marks on the hardware.
Which is correct in reference to electrical resistance?
If one of the three bulbs in a parallel lighting circuit is removed, the total resistance of the of the circuit will become greater.
(Refer to Figure 7.) If resistor R(3) is disconnected at terminal D, what will the ohmmeter read?
Infinite resistance.
Through which material will magnetic lines of force pass the most readily?
Iron.
(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?
Left gear up and right gear down.
Which of the following best describes the contributing factors to thermal runaway in a nickel-cadmium battery installed in an aircraft?
Low internal resistance intensified by high cell temperatures and a high current discharge/charge rate in a constant potential (voltage) charging system.
Which term means .001 ampere?
Milliampere
(Refer to Figure 15.) With the landing gear retracted, the red indicator light will not come on if an open occurs in wire
N0. 19.
(Refer to Figure 15.) When the landing gear is down, the green light will not come on if an open occurs in wire
No. 16
(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
No. 5.
(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
No. 6.
(Refer to Figure 16.) When electrical power is applied to the bus, which relays are energized?
PCC and TCC
Which effect does not apply to the movement of electrons flowing in a conductor?
Static energy.
What happens to the current in a voltage step-up transformer with a ratio of 1 to 4?
The current is stepped down by 1 to 4 ratio.
(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 open light will not illuminate.
When referring to an electrical circuit diagram, what point is considered to be at zero voltage?
The ground reference.
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°F.
What determines the amount of current which will flow through a battery while it is being charged by a constant voltage source?
The state-of-charge of the battery.
Which statement is correct when made in reference to a parallel circuit?
The total current is equal to the same currents through the individual branches of the circuit.
(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.
What will a voltmeter read if properly connected across a closed switch in a circuit with electrical power on?
Zero voltage.
Which of the following best describes the operating principal in a nickel-cadmium battery installed in an aircraft?
To completely charge a nickel-cadmium battery, some gassing must take place; thus, some water will be used.
What is the purpose of the ground symbol used in electrical circuit diagrams?
To show that there is a return path for the current between the source of electrical energy and the load.
Which is correct concerning a parallel circuit?
Total resistance will be smaller than the smallest resistor.
Which requires the most electrical power during operation? (Note: 1 horsepower = 746 watts)
Two lights requiring 3 amperes each in a 24-volt parallel system.
(Refer to Figure 9.) How many instruments (voltmeters and ammeters) are installed correctly?
Two.
What unit is used to express electrical power?
Watt.
Which of the following logic gates will provide an active high out only when all inputs are different?
XOR.
The working voltage of a capacitor in an ac circuit should be
at least 50 percent greater than the highest applied voltage.
In a P-N-P transistor application, the solid state device is turned on when the
base is negative with the respect to the emitter.
In an N-P-N transistor application, the solid state device is turned on when the
base is positive with respect to the emitter.
(Refer to Figure 23.) If R(2) sticks in the up position, the light will
be on full bright.
In nickel-cadmium batteries, a rise in cell temperature
causes a decrease in internal resistance.
(Refer to Figure 23.) If an open occurs at R(1), the light
cannot be turned off.
(Refer to Figure 17.) The electrical symbol represented at number 5 is a variable
capacitor.
(Refer to Figure 15.) The No. 7 wire is used to
close the PUSH-TO-TEST circuit
Forward biasing of a solid state device will cause the device to
conduct.
The method used to rapidly charge a nickel-cadmium battery utilizes
constant voltage and varying current.
What is the likely result of servicing and charging nickel-cadmium and lead acid batteries together in the same service area?
contamination of both types of batteries.
(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
crossfeed position.
The end-of-charge voltage of a 19-cell nickel-cadmium battery, measured while still on charge,
depends upon its temperature and the method used for charging.
Unless otherwise specified, any values given for current or voltage in an ac circuit are assumed to be
effective values.
Nickel-cadmium batteries which are stored for a long period of time will show a low liquid level because
electrolyte becomes absorbed into the plates.
When different rated capacitors are connected in parallel in a circuit, the total capacitance is (Note: C(T) = C(1) + C(2) + C(3) . . .)
equal to the sum of all capacitances.
When inductors are connected in series in a circuit, the total inductance is (where the magnetic fields of each inductor do not affect the others) (Note: L(T) = L(1) + L(2) + L(3) . . .)
equal to the sum of the individual inductances.
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.
The term that describes the combined resistive forces in an ac circuit is
impedance.
The electrolyte of a nickel-cadmium battery is the lowest when the battery is
in a discharge condition.
The electrolyte of a nickel cadmium battery is highest when the battery is
in a fully charged condition.
The correct way to connect a test voltmeter in a circuit is
in parallel with a unit.
The opposition offered by a coil to the flow of alternating current is called (disregard resistance)
inductive reactance.
The basis for transformer operation in the use of alternating current is mutual
inductive.
Transfer of electric energy from one circuit to another without the aid of electrical connections
is called induction.
Capacitors are sometimes used in dc circuits to
smooth out slight pulsations in current/voltage.
(Refer to Figure 1.) When different rated capacitors are connected in series in a circuit, the total capacitance is
less than capacitance at the lowest rated capacitor.
When calculating power in a reactive or inductive ac circuit, the true power is
less than the apparent power.
(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.
In an ac circuit, the effective voltage is
less than the maximum instantaneous voltage.
A fully charged lead-acid battery will not freeze until extremely low temperatures are reached because
most of the acid is in the solution.
Convert farads to picofarads by:
multiplying farads by 10 to the power of 12.
Convert farads to microfarads by
multiplying farads by 10 to the power of 6
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.
A thermal switch, or thermal protector, as used in an electric motor, is designed to
open the circuit in order to allow cooling of the motor.
(Refer to Figure 20.) Troubleshooting an open circuit with a voltmeter as shown in this circuit will
permit the battery voltage to appear to the voltmeter.
The amount of electricity a capacitor can store is directly proportional to the
plate area inversely proportional to the distance between plates.
The purpose of providing a space underneath the plates in a lead acid battery's cell container is to
prevent sediment buildup from conducting the plated of a sort circuit.
(Refer to Figure 18.) The control valve switch must be placed in the neutral position when the landing gears are down to
prevent the warning horn from sounding when the throttles at closed..
Diodes are used in electrical power supply circuits primarily as
rectifiers.
The voltage drop in a circuit of known resistance is dependent on
the amperage of the circuit.
When a charging current is applied to a nickel cadmium battery, the cells emit gas
toward the end of the charging cycle.
Typical application for zener diodes is as
voltage regulators
The potential difference between two conductors which are insulated from each other is measured in
volts.
(Refer to Figure 25.) In a functional and operating circuit, the depicted logic gate's output will be 0
when one or more inputs are 0.
