1)The current flow in a branch circuit is to be checked to determine if it is within the rated capacity of the circuit. The instrument best suited for this test would be:

a multimeter.

a clip-on ammeter

a neon test light.

either b or c

2)Which of the following can be used to provide information about the shape of a voltage waveform?

oscilloscope

multimeter

logic probe

neon test light

3)The type of screwdriver designed for use on screws with an 'X-shaped' insert in their heads is:

a Phillips screwdriver

a Robertson screwdriver.

a standard screwdriver.

a hexagon screwdriver.

4)An electromechanical relay is basically:

an electromagnet used to switch contacts.

an electromagnet used to operate motors.

an electronic circuit used to control motors.

a device designed to relay information.

5)Relays are primarily used to switch currents in the:

control circuit.

load circuit.

power-distribution circuit.

live circuit.

6)Which of the following is not a common application for a relay?

change alternating current to direct current

control a 120-V lighting circuit with a 24-V control circuit

control several switching operations by a single separate current

switch a high-current motor circuit ON and OFF with a low current control circuit

7)A particular relay is rated as follows: coil-9V DC, 200 mA: contacts-120 V AC, 10 A. What maximum number of 100-W, 120-V light bulbs could be safely controlled by this relay?

2

4

5

12

8)A particular relay is rated as follows: coil-9 V DC, 200 mA; contacts-120 V AC, 10 A. The resistance of the coil would be:

45 .

24 .

6,000 .

2,400 .

9)For an electromechanical relay, the amount of voltage and current required to energize the relay coil is:

the same when connected on an AC or a DC source.

the same as the voltage and current ratings of the contacts.

more than what is required to de-energize the coil

less than what is required to de-energize the coil.

10)Relays with sets of contacts, which are closed by some type of magnetic effect, are called:

electromechanical relays.

solid-state relays.

hybrid relays.

magnetic relays.

11)Relays with no contacts, which are switched entirely by electronic devices, are called:

electromechanical relays.

solid-state relays.

hybrid relays.

magnetic relays.

12)Solid-state relays use ____ as switching devices.

semiconductors

coils

contacts

permanent magnets

13)Which of the following is not an advantage of solid-state relays over electromechanical relays?

longer life

less electromagnetic interference generated

less susceptible to damage from voltage and current spikes

faster response time

14)The purpose of overload protection on a motor is to protect:

the motor from sustained overcurrents.

the wire from high currents.

the motor from sustained over voltage.

the motor from short circuits.

15)The current drawn by a motor is:

low on starting.

high on starting.

an accurate measurement of motor load.

both b and c

16)Which of the following is designed to provide machine operation protection by requiring the motor to be restarted after a power failure?

phase-reversal protection

ground-fault protection

low-voltage protection

low-voltage release

17)A contactor differs from a relay in that:

it operates on a different principle.

its contacts can interrupt large motor currents.

gravity and spring tension open contacts.

all of these

18)Technician A says a reduced-voltage starter is designed to apply full line voltage to the motor upon starting. Technician B says reduced-voltage starting produces a lower starting torque. Who is correct?

Technician A only

Technician B only

both Technician A and Technician B

neither Technician A nor Technician B

19)Which of the following starters increases the voltage gradually as the motor starts?

primary-resistance starter

autotransformer starter

wye-delta starter

solid-state starter

20)Which of the following applies to stopping a motor by electronically reversing the motor while it is still running in the forward direction?

dynamic braking

regenerative braking

plugging

jogging

21)Motor drive systems are used:

with AC or DC motors.

when operator-controlled variance of speed is required.

to maintain steady motor speed in spite of load fluctuations.

all of these

22)Which of the following is not a characteristic of AC motors?

high torque at low speed

lower cost

less maintenance required

physically smaller than DC motors of the same horsepower

23)In a variable-speed drive for a three-phase motor, which of the following circuits changes the DC power back to an adjustable frequency AC output?

rectifier

inverter

regulator

modulator

24)Sensors are used to detect the presence of and/or measure:

temperature.

position.

light.

all of these

25)The insulating material on a printed circuit board is called:

the laminate.

the dielectric.

the cladding.

the foil.

26)The foil pattern layout for a PC board shows:

all the interconnecting terminal strip connections.

the exact location of all the component parts.

all necessary conductor routing required for the working circuit.

all of these

27)Resist is any material which:

acts like a resistor.

offers resistance to the flow of current in a circuit.

will resist the chemical reaction used to etch copper.

all of these

28)The most commonly-used solder for soldering component leads to a PC board is:

20/80 bar solder.

40/40 solid wire solder.

60/40 resin-core wire solder.

50/50 acid-core wire solder.

29)A properly-soldered PC board connection will:

have low resistance.

appear shiny.

have no pin holes.

all of these

30) Large components that require considerable mounting space on a PC board are usually

integrated on to the board with very small components that require little space.

mounted at 90? to all other components.

shielded to prevent electrical interference.

left off the board completely and hand-wired.

31)When drilling lead access holes in a PC board:

moderate pressure should be applied to the drill.

heavy pressure should be applied to the drill.

the drill must be of a large enough diameter to completely remove the terminal pad copper foil.

both a and c

32)For mass production of printed circuit boards, the type of printing process most often used is:

the photo-etch method.

hand printing.

the print-and-etch technique.

machine printing.

33)When soldering on a PC board, the solder is always applied to:

the tip of the soldering iron only.

both the tip of the soldering iron and the component lead.

the junction of the lead and the terminal pad area.

the laminate.

34)Cleaning the copper foil of a PC board prior to soldering:

is only necessary if the foil appears dirty or dull.

is only necessary if a rosin based flux is not used.

is essential in all instances.

both a and b

35)A computer is basically a digital electronic system.

True

False

36)Computers are capable of storing large amounts of data.

True

False

37)Nonvolatile memory loses all its information when power is removed.

True

False

38)The computing power of a computer is determined by its wattage rating.

True

False

39)All computers are able to get data into and out of memory at approximately the same speed.

True

False

40)The input/output provisions for microprocessor-based systems are all basically the same.

True

False

41)The microprocessor uses only analog signals.

True

False

42)Types of output devices include instrumental displays and actuators.

True

False

43)MS-DOS is an example of a programming language.

True

False

44)Word processing is a type of computer applications software.

True

False

45)In any number system, the position of a digit that represents part of the number has a weighted value associated with it.

True

False

46)To express a number in binary requires fewer digits than in the decimal system.

True

False

47)Most digital logic circuits are constructed using integrated circuits.

True

False

48)Combinational logic circuits have no memory.

True

False

49)The primary function of a combinational logic circuit is to make decisions.

True

False

50)The only true mathematical operation performed by a computer is division.

True

False

51)The state of a flip-flop is determined by observing its Q output.

True

False

52)In a D flip-flop, the Q output is the same as the D input one clock pulse later.

True

False

53)Asynchronous is the term used to designate control by a clock pulse.

True

False

54)Binary counters are usually constructed using XOR gates.

True

False

55)An integrated circuit:

is a series of transistors mounted within a silicon chip.

refers to separately-produced components wired together with conductors to produce a complete circuit.

is a complete electronic circuit with all components and interconnecting wiring contained within a single chip of silicon.

is a series of separately-produced components wired within a printed circuit board.

56)Which of the following IC packages is extremely vulnerable to damage from static electricity?

DIP

digital

analog

MOS

57)The use of ICs:

is limited because of their high cost.

permits very complex circuits to have small physical dimensions.

is common in high-current circuits.

is common in high-voltage circuits.

58)Digital ICs contain:

amplifying-type circuitry.

resistors, capacitors, and transistors.

resistors, capacitors, and diodes.

switch-type circuitry.

59)Analog ICs contain:

amplifying-type circuitry.

resistors, capacitors, and transistors.

resistors, capacitors, and diodes.

switch-type circuitry.

60)The operational amplifier (op-amp) is:

a high-gain amplifier.

a type of analog IC.

used to amplify AC or DC signals.

all of these

61)The output power rating of an op-amp:

varies with the type of op-amp used.

is unlimited.

if exceeded, can damage the op-amp by overheating.

both a and c

62)An IC voltage comparator is basically:

an oscillator operated with a positive feedback circuit.

an oscillator circuit without a feedback circuit.

an op-amp operated with a negative feedback circuit.

an op-amp operated without a feedback circuit.

63)A 555 Timer IC is connected as a free-running oscillator. How can the output frequency be increased?

decrease the capacitance of the timing capacitor

increase the resistance of the timing resistors

increase the capacitance of the timing capacitor

decrease the input signal frequency

64)Technician A says the duty cycle of a pulse waveform is the percentage of the time the output is high. Technician B says the duty cycle of a pulse waveform is found by dividing the total ON time by the total OFF. Who is correct?

Technician A only

Technician B only

both Technician A and Technician B

neither Technician A nor Technician B

65)When troubleshooting most electronic circuits, 'loading effect' can be minimized by using a voltmeter with a/an:

input impedance much greater than the impedance across which the voltage is being measured

input impedance much less than the impedance across which the voltage is being measured

sensitivity of less than 1000 ohms/volt

sensitivity of more than 1000 volts/ohm

66)A semiconductor that decreases in resistance with an increase in temperature is known as a:

resistor

thermistor

diode

thermopile

67)The shunt used in an ammeter should be connected in.

series with the load and in parallel with the meter movement

parallel with the load and in series with the meter movement

parallel with the load and in parallel with the meter movement

series with the load and in series with the meter movement

68)External shunts are sometimes used with ammeters to:

increase meter sensitivity

permit shunts with larger resistances to be utilized

prevent damage to the meter movement from heat generated by the shunt

enable the construction of a compact meter with a virtually unlimited range

69)Which of the following statements represents an application of a silicon controlled rectifier?

To provide DC power for a main propulsion motor.

For use as a voltage reference diode.

For sensing flame in an automated burner.

To eliminate power supply hum.

70)An accidental path of low resistance, allowing passage of abnormal amount of current is known as a/an :

open circuit

short circuit

polarized ground

ground reference point

71)A resistance in a circuit of unknown value is to be tested using the voltmeter/ammeter method. Therefore, the meters should be connected with :

both meters in series with the resistance

both meters in parallel with the resistance

the ammeter in series and the voltmeter in parallel with the resistance

the ammeter in parallel and the voltmeter in series with the resistance

72)A direct current passing through a wire coiled around a soft iron core is the description of a simple :

magnetic shield

electromagnet

piezoelectric device

electromagnetic domain

73)The use of four diodes, in a full-wave bridge rectifier circuit, will :

provide unidirectional current to the load

allow a very high leakage current from the load

convert direct current to alternating current

offer high opposition to current in two directions

74)When troubleshooting electronic equipment, you should use a high impedance multimeter :

to prevent excess current flow through the meter that would damage it

for AC measurements only and a low resistance meter for DC measurements

whenever a low impedance meter is not available, regardless of the components being tested

so as not to load down the circuit and obtain erroneous voltage readings

75)Which of the listed devices is used to measure pressure and convert it to an electrical signal ?

Transducer

Reducer

Transformer

Rectifier

76)The device that most commonly utilizes the principle of electromagnetic induction is the :

diode

transformer

transistor

rheostat

77)Which of the following statements concerning analog and digital devices are correct?

The variables in digital systems are fixed quantities, and the variables in analog systems are continuous quantities.

There are no basic differences between the two systems.

Analog devices are superior in accuracy compared to digital devices.

Operations in a digital device are performed simultaneously.

78)The Wheatstone bridge is a precision measuring instrument utilizing the principle of changes in :

inductance

capacitance

resistance

amperage

79)Which of the listed logic gates is considered to be a BASIC building block (basic logic gate) used in logic diagrams?

NAND

OR

NOR

All of the above.

80)Heat sinks are frequently used with :

power transistors

vacuum tubes

tunnel rectifier diodes

all of the above

81)The first requirement for logical troubleshooting of any system is the ability to :

collect all available data on a casualty

recognize normal operation

identify the probable cause of a symptom

isolate the faulty component

82)A fuse that blows often should be replaced only with a fuse of :

the recommended current and voltage rating

higher current and voltage rating

higher current and lower voltage rating

lower current and higher voltage rating

83)Which of the listed conditions is an advantage of a PN diode over a vacuum diode?

Longer life.

No warm up time.

Less delicate.

All of the above.

84)The heating of conductors as a result of resistance in a distribution circuit causes a power loss expressed as :

line droop

line loss

IR drop

hysteresis

85)In process control terminology values which can change without distinct increments, such as temperature, pressure, or level are called :

binary values

digital values

bumpless values

analog values

86)Silicon diodes designed for a specific reverse breakdown voltage, become useful as an electronic power supply voltage regulator, called :

tunnel diodes

hot-carrier diodes

compensating diodes

Zener diodes

87)The type of feature afforded auxiliaries vital to the operation of propelling equipment, where automatic restart after a voltage failure would not create a hazard, is termed :

low voltage protection

high amperage protection

low voltage release

high amperage release

88)Which of the following statements correctly applies to transistors?

NDN and PNP are the two basic types of transistors.

The three terminals are called the emitter, base, and collector.

The emitter separates the base and collector.

The collector separates the emitter and base.

89)The basic measuring unit of inductance is the :

coulomb

ohm

farad

henry

90)Alternating current circuits develop resistance, inductance and capacitance. The inductance of a coil is expressed in :

ohms

mhos

henrys

farads

91)An insulation resistance test is performed on a particular piece of electric equipment. In addition to the resistance reading, what information listed below should be entered in the electrical log?

The maximum allowable operating temperature of the machine.

The temperature of the machine at the time the resistance reading was taken.

The normal temperature rise of the machine.

The complete nameplate data from the resistance test instrument used to obtain the reading.

92)Alternating current circuits develop resistance, inductance, and capacitance. The capacitance of individual capacitors is expressed in :

ohms

mhos

henrys

farads

93)Which of the following statements represents the important factor that must be considered when replacing a faulty diode in the exciter rectifier assembly?

Be certain that the replacement diode is the same polarity as the one removed.

Never alter the diode alignment to cause a change in the neutral plane.

Replacement of a diode also requires balancing of the rotor with a one-piece rotor lamination to be shrunk fit and keyed to the shaft.

The replacement diode must be dipped in varnish prior to installation to protect against humidity.

94)The insulation resistance of electric equipment and machinery should be tested for the lowest normal insulation values :

immediately after shutting down the machine

every time the brush rigging is adjusted

immediately after starting up the machine

every 30 days whether the machine is in use or not

95)A triac thyristor functions as a control device and is basically :

two NPN transistors in parallel with a common base lead

a diode in series with a temperature sensitive capacitor

two back-to-back SCR's with a common gate lead

a triode tube with an extra heavy grid element

96)The apparent power in a purely inductive circuit is also known as :

true power

lead power

induced power

reactive power

97)The multiple prefix 'giga' (G) means :

thousand (10 to the 3rd power)

million (10 to the 6th power)

billion (10 to the 9th power)

trillion (10 to the 12th power)

98)Copper is often used as an electrical conductor because it :

has high resistance at low temperatures

has a highly polished surface

is able to pass current with little opposition

holds insulation together well

99)The unit of apparent power in a purely inductive circuit is called the :

kva

var

emf

watt

100)A grounded switch or cable will be indicated by a megohmmeter reading of :

infinity

'zero'

being unsteady in the high range

being unsteady in the low range

101)The multiple prefix 'kilo' means :

thousand (10 to the 3rd power)

million (10 to the 6th power)

billion (10 to the 9th power)

trillion (10 to the 12 power)

102)An adjustable resistor, whose resistance can be changed without opening the circuit in which it is connected, is called a :

bleeder resistor

rheostat

bridge

variable shunt strip

103)The purpose of a heat sink, as frequently used with transistors, is to :

prevent excessive temperature rise

compensate for excessive doping

increase the reverse current

decrease the forward current

104)The combined effect of inductive reactance, capacitive reactance, and resistance in an AC series circuit is known as :

reactance

total reactance

impedance

resonance

105)In a DC series circuit, all the conductors have the same :

power expended in them

voltage drop across them

resistance to current flow

current passing through them

106)AC circuits develop resistance, inductance, and capacitance. The inductive reactance of a circuit is expressed in :

ohms

mhos

henrys

farads

107)A silicon controlled rectifier (SCR) is a solid state device used to change :

DC to AC and control relatively low load current

AC to DC and control relatively high load current

DC to AC and control relatively high load current

AC to DC and control relatively low load current

108)The basic control action of a magnetic amplifier depends upon :

variations in the load capacitance

changes in inductance

type of core material

construction of the core

109)The process, whereby electrons gain sufficient energy to be released from the surface of a thin, heated metal plate, is known as :

photo electric emission

secondary emission

thermionic emission

regressive emission

110)Most conducting materials such as copper, aluminum, iron, nickel, and tungsten :

increase in resistance with increased temperature

increase in resistance with decreased temperature

decrease in resistance with increased temperature

increase in conductance with increased temperature

111)In a series circuit, which value will remain unchanged at all places in the circuit?

Voltage

Current

Resistance

Inductance

112)In electronic circuitry, the abbreviation 'PCB' commonly means ______________.

pulse coded binary

printed circuit board

poly-coated braid

personal computer bits

113)Which of the listed conditions describes the effect on intrinsic semiconductor operation as a result of a temperature increase?

Additional heat sinks will be required

Conductivity will increase

Conductivity will decrease

Resistivity will increase

114)In electronic circuits, DC voltages can be positive (+) or negative (-) when measured with respect to the :

printed circuit board 'common' trace

chassis, console frame or hull 'ground'

analogue or digital circuitry 'common' bus

all of the above

115)Capacitors are used on the output of the power supply in today's consoles to :

filter out 'ripple'

prevent overloads

act as a permanent load

decrease the average value of the output voltage

116)Operational amplifiers, used primarily in analog circuits, are characterized by :

high input impedance, high gain and low output impedance

high input impedance, high gain and high output impedance

low input impedance, low gain and high output impedance

low input impedance, high gain and low output impedance

117)Reversing the current flow through a coil will :

reduce the amount of flux produced

have no effect on the eddy currents produced

reduce the power consumed

reverse its two-pole field

118)The schematic symbol for an operational amplifier in an analog circuit is a :

circle

square

trapezoid

triangle

119)The total resistance of a parallel circuit is always :

larger than the greatest branch resistance

smaller than the lowest branch resistance

equal to the sum of the individual branch resistances

one-half the sum of the individual branch resistances

120)Which of the following expresses the relationship of the input and output frequencies in a full wave rectifier?

The output frequency is the same as input frequency.

The output frequency is one-half the input frequency.

The output frequency is twice the input frequency.

The output frequency is four times the input frequency.

121)A temperature instrumentation system for an engine room console consists of a resistance temperature detector (RTD), a measuring bridge circuit, and a meter (or alarm circuit).Which of the following statements is true concerning the measuring bridge circuit :

The input voltage varies in a linear fashion with temperature.

The voltage across the center of the resistance bridge is always constant.

The resistance bridge is said to be balanced when its output voltage is zero.

The input voltage of the resistance bridge is the constant temperature signal.

122)One feature of the operational amplifier is that it can have :

up to ten outputs

binary coded decimal inputs

several hundred amps at the output

inverting and non-inverting inputs

123)A signal derived from a controlled function and returned to the initiating point is called a/an :

monitoring signal

inverse signal

reverse signal

feedback signal

124)A semiconductor is a material with a :

conductivity higher than a normal conductor

conductivity higher than a normal insulator

high conductivity at low temperatures

low conductivity at high temperatures

125)A capacitor can be tested using a megohmmeter or an ohmmeter. If the meter is connected to a shorted capacitor, the meter pointer should :

immediately swing to the maximum resistance value for the capacitor

first swing quickly to 'zero', then gradually move up the scale as the capacitor charges

immediately deflect to and remain at zero

immediately swing to a high reading and then gradually decrease

126)To provide its unique characteristics to analog circuits, the operational amplifier is made up of a/an :

voltage amp, current amp and output amp

input amp, power amp and output amp

scaling amp, power amp and voltage amp

differential amp, voltage amp and output amp

127)When replacing a power transistor fitted with a heat sink in a circuit, a coating of silicone grease is applied between the transistor case and the heat sink. This is done to :

lubricate the transistor

lubricate the heat sink

aid in the removal of the heat sink

provide maximum heat transfer

128)The resistance of a conductor varies :

directly as its length and inversely as its cross-sectional area

inversely as its length and directly as its cross-sectional area

directly as its length and directly as its cross-sectional area

inversely as its length and inversely as its cross-sectional area

129)In order to check the performance of a transistor removed from its circuit, the instrument to be used should be a/an :

voltmeter or transistor tester

impedance meter

ohmmeter or transistor tester

sensitive potentiometer

130)When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter's pointer :

dipping toward zero then raising slowly

continually rising as test voltage is applied

kicking slightly down scale as voltage is applied

fluctuating around a constant resistance reading

131)Which of the following actions can be carried out in order to prevent thermal runaway in a transistor?

Increase the current through the collector-base junction.

Install a heat sink.

Shift the 'Q' point to increase collector current.

Increase the potential difference between the emitter and the base.

132)Basic operating characteristics of the operational amplifier such as gain and stability are the function of its :

differential input stage

power output stage

feedback circuit

supply voltages

133)Possible phase relationships between voltage and current in an alternating current circuit include which of the following conditions?

Current and voltage may be in phase.

Current may lead the voltage.

Current may lag the voltage.

All of the above.

134)A suspected 'open' in a motor field can be tested by using a/an :

potentiometer

ohmmeter

wattmeter

ammeter

135)The sub-multiple prefix 'nano' (n) means :

thousandth (10 to the -3rd power)

millionth (10 to the -6th power)

billionth (10 to the -9th power)

trillionth (10 to the -12th power)

136)A switchboard, for a AC electrical distribution system, will be provided with which of the following components?

Frequency meter.

Ammeter

Voltmeter

All of the above

137)Which of the procedures listed could result in damaging a transistor beyond repair?

Applying incorrect polarity to the collector circuit.

Applying excessive voltage to the input circuit.

Careless soldering which would overheat the transistor.

All of the above.

138)Basically, a magnetic amplifier is a saturable reactor with the addition of :

AC to the bias winding

variable capacitance to all windings

eddy current protectors

a rectifier in the load circuit

139)Which of the electrical properties listed will always be the same for each component in a parallel circuit?

Impedance

Current

Resistance

Voltage

140)Which of the listed instruments can be best used to locate a grounded field coil in a synchronous motor?

Frequency meter

Megohmmeter

Voltmeter

Multimeter

141)A capacitor discolored due to excessive heat should be :

calibrated

replaced

cooled

soldered

142)A covalent bond:

bonds atoms in pure semiconductor materials.

involves the sharing of outer shell electrons.

produces the equivalent of an atom with a full outer shell.

all of these

143)If a silicon crystal is doped with a material having five valence electrons:

an insulator is formed.

its resistance goes up.

a P-type semiconductor is formed.

an N-type semiconductor is formed.

144)If a germanium crystal is doped with a material having three valence electrons:

a conductor is formed.

an insulator is formed.

a P-type semiconductor is formed.

an N-type semiconductor is formed.

145)In a PN-junction diode, the depletion region is formed by:

applying forward bias across the diode.

heating the diode to a high temperature.

electrons crossing the junction and filling the holes.

current flowing from anode to cathode.

146)A PN-junction diode is said to be forward- or reverse-biased depending on:

the type of dopant used.

the polarity of the AC voltage applied across it.

the polarity of the DC voltage applied across it.

all of these

147)Excessive reverse-bias voltage may cause a silicon diode to:

avalanche.

reverse its polarity.

turn OFF.

become an insulator.

148)When checking a diode with an ohmmeter, a good diode would be indicated by:

a low-resistance reading in both directions.

a high-resistance reading in both directions.

a zero-resistance reading in both directions.

a low-resistance reading in the one direction and a high-resistance reading in the other.

149)A diode rated for 35-V peak forward-bias voltage is used in a circuit rated for a peak forward-bias voltage of 24 V. The diode will:

operate normally.

not operate at all.

operate normally but will not last as long.

operate, but with different characteristics.

150)A light-emitting diode (LED) will:

conduct a current in one direction only.

give off light when current flows through it.

consume less energy than a filament-type light bulb.

all of these

151)The laser diode has a(n) ____ which is required for lasing production.

optical cavity

depletion area

hole current carriers

electron current carriers

152)The three leads of a bipolar junction transistor are:

the anode, the base, and the cathode.

the emitter, the gate, and the anode.

the base, the collector, and the emitter.

the grid, the anode, and the cathode.

153)Field-effect transistors (FETs) operate:

on the same principle as magnetic field devices.

with a small input voltage and current.

with a small input voltage but practically no input current.

with high input current.

154)The PNP transistor is the complement of the NPN transistor. This means:

that the two operate on different principles.

that one can be replaced by the other in a given circuit, and it will still operate.

that the two are electrically similar except that opposite current and voltages are involved.

that one is designed to operate from an AC source and the other from a DC source.

155)A bipolar-junction transistor circuit is operated so that:

a small change in base current controls a large change in collector current.

a small change in collector current controls a large change in base current.

a small change in collector current controls a large change in emitter current.

a small change in emitter current controls a large change in collector current.

156)The drain current produced by a properly biased N-channel junction FET will decrease when the FET's gate is:

made more negative with respect to its source.

made less negative with respect to its source.

shorted to its source to reduce VGS to zero.

subjected to a potential, which decreases the size of the depletion region.

157)The input resistance of a junction FET will remain extremely high as long as the FET's gate-to-channel junction is:

biased so that the FET is operating in the enhancement mode.

biased so that the gate current flows.

forward-biased.

reverse-biased.

158)An insulated-gate FET will maintain a high input resistance when its gate is made:

positive only.

negative only.

positive or negative with respect to its source.

to conduct a low reverse current.

159)To protect MOSFETs against static charges:

the leads are coated with a varnish insulation.

the leads are shorted together until they are placed into a circuit.

they are shipped in special static-protection packages.

both b and c

160)A unijunction transistor (UJT):

operates similar to a bipolar transistor.

operates similar to a field-effect transistor.

does not amplify.

none of these

161)When a UJT switches to the ON state, current is conducted between:

collector and emitter.

base 1 and base 2.

emitter and base 1.

all of these

162)The main application for SCRs and triacs is:

as audio amplifiers.

as oscillators.

for control of current in the milliampere range.

for control of power in the watt or kilowatt range.

163)A silicon-controlled rectifier (SCR) is normally biased so that it can be turned ON by:

momentarily increasing its forward voltage.

increasing its reverse voltage.

momentarily applying a gate current.

momentarily decreasing its gate current.

164)When an SCR circuit is operated from an AC source:

the gate can be used to switch the circuit ON and OFF at all times.

once switched ON by the gate, the circuit can not be switched OFF by the gate.

the output is always DC.

both a and c

165)In order for an SCR to be triggered into conduction:

the anode must be positive with respect to the cathode.

both the anode and the gate must be positive with respect to the cathode.

the anode must be negative with respect to the cathode.

the gate must be positive with respect to the cathode.

166)SCR phase-shift control circuits are used to vary the ____ between the trigger pulse and the point in the conducting cycle when the pulse occurs.

power delivered

time relationship

different points

motor speed

167)____ of the positive half-cycle will be conducted to the load, depending on when the SCR fires.

All

None

Part

all of these

168)How is a silicon-controlled rectifier similar to a diode rectifier?

Both conduct current in one direction only.

Both can be classified as thyristors.

Both have one PN junction.

all of these

169)The main difference between the operation of an SCR and a triac is:

an SCR produces less heat than a triac during normal operation.

an SCR is a switching device, while a triac is an amplifying device.

an SCR can be triggered into conduction in only one direction.

an SCR is made of silicon but a triac is not.

170)An out-of-circuit ohmmeter check of a non-defective 24-V diac should indicate:

a high resistance reading in both directions.

a low resistance reading in both directions.

a high resistance reading in one direction and a low resistance reading in the other.

zero resistance in one direction and infinite resistance in the other.

171)Breakover voltage of a diac is:

never to be exceeded.

the point at which its resistance changes from high to low.

the same as avalanche voltage.

always less than 0.6 V.

172)The joule is the base unit of:

energy

work

neither of the above

both of the above

173)The part of the atom that has no electric charge is the:

neutron

nucleus

neither of the above

both of the above

174)A positive charge can:

attract a negatively charged object

attract and then repel a neutral object

neither of the above

both of the above

175)The nucleus of most atoms contain:

neutrons

protons

neither of the above

both of the above

176)A negative ion has an excess of:

electrons

protons

neither of the above

both of the above

177)A proton has:

a positive electric charge

a negative electric charge

neither of the above

both of the above

178)Electrons in the outermost shell of an atom are called:

free electrons

valence electrons

neither of the above

both of the above

179)When an electron becomes a free electron its energy level is:

cut in half

unchanged

doubled

none of the above

180)The base unit of charge is the:

ampere

coulomb

ohm

volt

181)The joule is the base unit of:

energy

current

power

resistance

182)Kilowatthour is a unit of:

charge

energy

power

time

183)A wattsecond is equal to a(n):

ampere

coulomb

joule

volt

184)The charge possessed by 6.25 x 1018 electrons equals one:

ampere

coulomb

joule

volt

185)A coulomb per second equals the base unit of:

current

power

resistance

voltage

186)Joule per coulomb is the definition of a:

watt

ohm

coulomb

volt

187)The amount of resistance is expressed in:

watts

ohms

coulombs

volts

188)A current of 0.04 A could also be expressed as:

4 x 10-3 A

400 A

40 mA

0.4 kA

189)In addition to Ohms law, solving multiple-load circuits requires the use of:

Coulombs laws

Amperes laws

Kirchhoffs laws

none of the above

190)The formula that can be used in any type of circuit is:

IT= IR1 + IR2 + IR3 + etc.

RT= RR1 + RR2 + RR3 + etc.

PT= PR1 + PR2 + PR3 + etc.

none of the above

191)RTis always greater than R1 in:

a series circuit

a parallel circuit

a series-parallel circuit

both B and C above

192)IR1is always less than IT in:

a series circuit

a parallel circuit

a series-parallel circuit

both A and C above

193)A condition that is necessary for maximum power transfer is:

Rsource= Rload

Rsource= 10Rload

10 x Rsource = Rload

100 x Rsource = Rload

194)The smallest resistance always dissipates the most power in:

a series circuit

a parallel circuit

a series-parallel circuit

both b and c above

195)The largest resistance always drops the most voltage in:

a series circuit

a parallel circuit

a series-parallel circuit

both a and c above

196)For the circuit below, PT is equal to:

40 mW

0.04W

320 mW

none of the above

197)For the circuit below:

RT= 1 k

PR2= 533 mW

PT= 1.6 W

all of the above

198)For the circuit below:

IR3= 4 mA

IR2= 8 mA

neither of the above

both of the above

199)Solving simultaneous equations requires:

no more than two independent equations

at least three independent equations

as many independent equations as there are unknown variables

one fewer independent equations than unknown variables

200)The technique that cant be used on single-source circuits is:

loop equations

superposition theorem

Nortons theorem

none of the above

201)The technique that cant be used on multiple-source circuits is:

loop equations

superposition theorem

Thevenins theorem

none of the above

202)The technique that uses only series-parallel rules and procedures is:

loop equations

superposition theorem

Nortons theorem

none of the above

203)The technique that may not determine all current and voltage values is

loop equations

superposition theorem

Nortons theorem

none of the above

204)The technique that may require the use of another technique before it can be applied is:

loop equations

superposition theorem

Thevenins theorem

all of the above

205)The technique that requires only one calculation to determine the new load current when the load resistance is changed is:

loop equations

superposition theorem

Nortons theorem

none of the above

206)The technique that may yield a negative value of current is:

loop equations

superposition theorem

Nortons theorem

all of the above

207)Determine the value of IR2, IR3, and VR2 in the circuit below.

IR2= 1.25 mA, IR3 = 1.75 mA, VR2 = 3 V

IR2= 2.05 mA, IR3 = 1.99 mA, VR2 = 3 V

IR2= 3.98 mA, IR3 = 2.09 mA, VR2 = 4 V

IR2= 7.90 mA, IR3 = 3.00 mA, VR2 = 5 V

208)The direction of the flux around a conductor can be determined by:

the left-hand rule and the polarity of the applied voltage

the left-hand rule and the direction of the current flow

either of the above

neither of the above

209)The invisible lines of force around a magnet are called:

magnetic flux

mmf

poles

reluctance

210)When the currents in two parallel conductors are in the same direction:

the flux produced by one conductor cancels the flux from the other conductor

the conductors attract each other

the conductors repel each other

none of the above

211)The most magnetic element is:

cobalt

nickel

silicon

iron

212)Increasing the space between the turns in a coil:

increases the flux at the poles

decreases the flux at the poles

does not change the flux at the poles

none of the above

213)The flux associated with a temporary magnetic material after the material is removed from a magnetic field is called:

resident magnetism

retained magnetism

induced magnetism

none of the above

214)The unit used to specify flux density is the:

ampere-turn

tesla

weber

none of the above

215)The unit for permeability is the:

ampere-turn

tesla

weber

none of the above

216)Magnetic shields are usually made from:

nonmagnetic materials

temporary magnetic materials

permanent magnetic materials

none of the above

217)The most common waveform for ac is the:

triangle wave

sawtooth wave

square wave

sine wave

218)One cycle of an ac waveform:

has two alternations

reverses polarity once

neither of the above

both of the above

219)The rate at which cycles are produced is called the:

cycle

frequency

period

rapidity

220)One cycle per second is equal to:

a hertz

a period

an alternation

none of the above

221)Unless otherwise specified, ac values are assumed to be:

effective values

average values

peak values

none of the above

222)One cycle spans:

90 electrical degrees

120 electrical degrees

180 electrical degrees

360 electrical degrees

223)The phase voltages in a three-phase system are separated by:

90 electrical degrees

120 electrical degrees

180 electrical degrees

360 electrical degrees

224)When the T = 2 ms, f will equal:

0.5 Hz

50 Hz

500 Hz

none of the above

225)The f of an eight-pole generator rotating at 600 r/min will be:

4800 Hz

2400 Hz

80 Hz

40 Hz

226)In a wye-connected three-phase system, the relationship between the magnitudes of the phase and the line voltages is:

1.732Vline = Vphase

Vline= 1.732 Vphase

Vline= 1.414 Vphase

Vline= 0.707 Vphase

227)The particles that can be found within an atom are:

electrons and protons.

protons and neutrons.

neutrons, protons, and electrons.

electrons, molecules, and protons.

228)The smallest negative particle of electricity is called:

an electron.

a neutron.

an element.

a proton.

229)The weight of a proton is:

much greater than that of an electron.

much less than that of an electron.

much less than that of a neutron.

much greater than that of a neutron.

230)A negatively charged ion has:

more electrons that protons.

fewer electrons than protons.

a complete outer electron shell.

an incomplete outer electron shell.

231)The outer-shell electrons of an atom:

are called valence electrons.

are set free most easily.

become free electrons once they are set free.

all of these

232)Electrons are held in their orbital path by:

centrifugal forces counterbalancing attraction forces.

centrifugal forces only.

attraction forces only.

unlike electrical forces.

233)A good insulator of electricity is a substance that:

is used to conduct an electric current.

is a metal.

has 1, 2, or 3 valence electrons.

is used to prevent the flow of electrons.

234)A transistor can be classified as:

a conductor.

an insulator.

a pure semiconductor.

a specially-treated semiconductor.

235)A continuity tester is basically:

a series circuit consisting of a battery, switch, and test leads.

a parallel circuit consisting of a battery, light bulb, and test leads.

a parallel circuit consisting of a battery, switch, and test leads.

a series circuit consisting of a battery, light bulb, and test leads.

236)A continuity tester is used to check a fuse. When the fuse is connected across the test leads, a blown fuse is indicated when:

the lamp comes on with full brightness.

the lamp comes on with approximately half the normal brightness.

the lamp does not come on at all.

either a or b

237)Static electricity is:

the same as alternating current.

the same as direct current.

an electrical charge in motion.

an electrical charge at rest.

238)When a hard rubber rod and a piece of fur are rubbed together, the fur gives up electrons to the rubber rod. As a result:

the fur and rod become positively charged.

the fur and rod become negatively charged.

the rod becomes positively charged.

the rod becomes negatively charged.

239)The law of electric charges states:

like charges can neither repel nor attract.

like charges repel, unlike charges attract.

unlike charges can neither repel nor attract, whereas like charges can both repel and attract.

unlike charges repel, like charges attract.

240)Current electricity:

is an electric charge in motion.

can be classified as being AC.

can be classified as being DC.

all of these

241)When a charge is transferred without direct physical contact, this is known as charging by:

induction.

conduction.

deduction.

friction.

242)When an alternating current power source is connected to a circuit, it produces a current that:

changes in direction, but not in magnitude.

changes in magnitude, but not in direction.

does not change in magnitude or direction.

changes in both direction and magnitude.

243)Voltage is produced in a battery by means of:

heat.

light.

a chemical reaction.

a solar cell.

244)A device that produces a voltage when put under pressure is:

a battery.

a generator.

a solar cell.

a crystal.

245)Large amounts of electricity are usually produced using:

a battery.

a solar cell.

a thermocouple.

a generator.

246)In the battery, or voltaic cell, electrons are transferred from one electrode to the other. The electrode that gains electrons is:

the negative terminal.

the positive terminal.

the electrolyte.

both a and c

247)Technician A says that when taking measurements with a voltmeter and an ammeter, the meters are both connected into the circuit in the same way. Technician B says the voltmeter is connected in series and the ammeter is connected in parallel. Who is correct?

Technician A only

Technician B only

both Technician A and Technician B

neither Technician A nor Technician B

248)The force that causes the flow of electrons through a conductor is known as:

the power.

the current.

the voltage.

the resistance

249)The unit of measurement for the difference of potential between two points is:

the volt

the ampere.

the PD.

the ohm

250)An electric toaster is rated for 220 V and 10 A. Its power rating would be:

2200 W

2200 Wh

2200 kWh

2200 J

251)Which of the following is an example of a voltage source?

a battery

a light bulb

a switch

copper wire conductors

252)In a basic electrical circuit, the part that stores electric energy or changes it into other forms is:

the load.

the source.

the conductor(s).

the switch.

253)Electrical conductors:

have high resistance.

use most of the energy available from the source.

complete the electron path from the source to the load.

all of these

254)Which of the following is an example of a load?

an electrical wall outlet

a hair dryer

a pushbutton

an extension cord

255)Which of the following is classified as a protective device?

a pushbutton

a fuse

a circuit breaker

both b and c

256)A switch would be classified as:

a control device

a protective device.

a load device.

a voltage source.

257)A poorly made electrical connection:

has a much higher-than-normal resistance.

can produce excessive heat when normal current flows through the circuit.

can reduce the total energy normally available for the load.

all of these

258)For practical purposes, all the circuit resistance is considered to be contained in:

the load device.

the conductors or wires.

the control device.

the protective device.

259)The purpose of the energy source is to:

protect circuit wiring and equipment.

start, stop, or vary the electron flow.

supply the voltage required to move the free electrons

all of these.

260)A fuse is used to:

protect circuit wiring and equipment.

allow only currents within safe limits to flow.

automatically open the circuit when a higher current flows.

all of these.

261)Which of the following electrical diagrams is easiest to read?

pictorial

wiring

perspective

schematic

262)A string of lamps is connected in parallel to a voltage source. If one lamp burns out, all the other lamps:

will go out.

will get brighter.

will not be affected.

will get dimmer.

263)A string of lamps are connected in series to a voltage source. This connection would result in:

two voltage paths.

one voltage path

one current path.

two current paths.

264)An AND-type control circuit consists of switches connected in:

parallel.

parallel and series combination.

series.

series and parallel combination.

265)If a circuit is constructed to allow the electrons to follow only one possible path, the circuit is called:

a series-parallel circuit.

an open circuit.

a series circuit

a parallel circuit.

266)Two switches are connected to control a lamp. A ____ can be used to show how the switches work the lamp.

truth table

wiring sequence chart

block diagram

all of these

267)Replacing a fuse with one of a higher current rating can cause:

lights in a house to flicker.

a short circuit.

wiring to overheat.

all of these

268)One of the factors involved in an electric shock is body resistance. Which of the following statements about body resistance is not true?

The higher the body resistance, the greater the potential shock hazard.

The lower the body resistance, the greater the potential shock hazard.

The wetter the skin, the greater the potential shock hazard.

The drier the surface that a person is standing on, the greater the body-to-surface electrical resistance.

269)Generally, any voltage above ____ V is considered dangerous.

9

48

110

220

270)The severity of an electric shock increases with:

an increase in voltage levels.

an increase in body current flow.

a decrease in body resistance.

all of these

271)Resistance wire is designed primarily to convert electricity energy into:

sound.

heat

mechanical energy

magnetism.

272)When a resistor has a 2-W rating, this means that it:

can safely dissipate 2 W, or less, of power.

always dissipates exactly 2 W of power.

always provides 2 W of power.

all of these

273)Which resistor would you choose if you were asked to pick a resistor to use on a printed-circuit board circuit in which a large number of identical resistors were required?

precision resistor

resistor network

wire-wound resistor

trim pot

274)Which of these variable resistors would most likely be used to control current in a higher power-level circuit?

rheostat

trimmer potentiometer

nonlinear potentiometer

linear potentiometer

275)A voltage divider is formed by connecting a 6-kresistor and a 2-k resistor in series across a 20-V source. The voltage drop across each resistor would be, respectively:

15 V and 5 V

8 V and 12 V.

6 V and 4 V.

4 V and 6 V.

276)The symbol for the prefix micro (metric measure) is:

m.

M

mic

277)A 470,000 resistor may be designated as:

47 M

470 k

47 k

4,7 M

278)Converting 1 mA to its base unit produces:

0.1 A.

0.001 A

10,000 A

100,000 A.

279)A voltage of 0.48 V can be expressed as:

4800 mV.

480 mV.

48 mV.

4.8 mV.

280)Ohm's law states that:

current is directly proportional to the resistance and inversely proportional to the voltage.

voltage is directly proportional to the current and inversely proportional to the resistance.

current is directly proportional to the voltage and inversely proportional to the resistance

voltage is directly proportional to the resistance and inversely proportional to the current.

281)Technician A says that in a electrical circuit, voltage can exist without current. Technician B says that current cannot exist without voltage. Who is correct?

Technician A only

Technician B only

both Technician A and Technician B

neither Technician A nor Technician B

282)How much current will a 0.75 car rear window defogger draw when connected to a 12-V battery source?

9 A

12 A

16 A

18 A

Explicaii:

283)The current flowing through a 72 resistor is measured and found to be 0.5 A. How much voltage is being applied across the resistor?

90 V

9 V

360 V

36 V

284)What is the resistance of a soldering iron element that conducts a current of 4 A when connected to a 120-V electric outlet?

480 ohm

360 ohm

160 ohm

30 ohm

285)If a voltage of 3 V is applied across a resistor of 9 how many watts of power does the resistor dissipate?

27 W

9 W

3 W

1 W

286)A series circuit has:

one pathway for current flow.

two pathways for current flow

three pathways for current flow.

as many pathways for current flow as there are loads connected in series

287)In a series circuit, the amount of voltage each load receives is:

the same as the applied voltage.

inversely proportional to the resistance value of the load.

directly proportional to the resistance value of the load.

determined by its position in the series string.

288)Three resistors (R1, R2, and R3) are connected in series to a 120-V source. The values of V1 and V3 are measured and found to be 42 V and 8 V, respectively. The value of V2 would then be:

40 V

24 V

70 V

56 V

289)How much resistance R1 must be added in series with a 400 R2 to limit the current to 0.25 A with 120 V applied?

50

100

200

80

290)Resistors R1 - 8 k, R2 - 4 k, R3 - 6 k, and R4 - 2 kare connected in series to a voltage source. Which resistor will dissipate the most power?

R1

R2

R3

R4

291)Three resistors with values of 1 k, 5 k, and 3 k, respectively, are connected in series with a fourth resistor of unknown value. The applied voltage is 120 V and the current flow is 5 mA. What is the resistance value of the unknown resistor?

15 kOhm

8 kOhm

4.5 kOhm

3.2 kOhm

292)A string of twelve holidy lamps is designed to be connected in series to a 120-V source. If one of the lamps burned out and was shorted from the circuit, the operating voltage across each of the other eleven lamps would be:

10.9 V

20 V

32 V

48 V

293)Which resistor of a series circuit receives the largest voltage drop?

the first resistor in the string

the last resistor in the string

the one with the least resistance

the one with the most resistance

294)The polarity of the voltage drop across a resistor depends on:

its resistance value.

its position in the circuit.

the direction of current flow through it.

all of these

295)Two voltage sources are connected series-opposing. Technician A says the two voltages are added to obtain the total equivalent voltage. Technician B says the equivalent voltage is given the polarity of the greater voltage. Who is correct?

Technician A only

Technician B only

both Technician A and Technician B

neither Technician A nor Technician B

296)With 24 V applied across five 6 resistors in parallel, the total current equals ____.

10 A

6 A

20 A

2 A

297)With two resistances connected in parallel, if each dissipates 5 W, the total power supplied by the voltage source equals:

4 W

6 W

8 W

10 W

298)With two resistances connected in parallel:

the current through each must be the same.

the voltage across each must be the same.

their combined resistance equals the sum of the individual values.

both b and c

299)Resistors of 10 and 30 are connected in parallel to a 120-V supply. The current flow through the 10 resistor would be:

12 A

8 A

4 A

3 A

300)A three-branch parallel resistor circuit is connected to a 6-V source. The branch currents are 1.2 A, 800 mA, and 250 mA, respectively. The total current is:

less than 1.2 A

less than 800 mA.

about 1050 mA.

about 2.25 A

301)Four resistors, 1 keach, are connected in parallel. This group is connected to a 9-V source. The combined resistance of the group is:

100 Ohm

150 Ohm

200 Ohm

250 Ohm

302)Four resistors, 1 keach, are connected in parallel. This group is connected to a 9-V source. The current in the line leading to the group of resistors is:

12 mA

18 mA

36 mA

500 mA

303)The voltage across an open component in a parallel circuit is always equal to:

the source voltage

the dropped voltage.

the lowest circuit voltage.

zero.

304)With a short in one of the branches of a parallel circuit:

the voltage source is shorted out.

the voltage source will deliver its maximum current flow.

the total circuit resistance drops to near zero resistance.

all of these

305)Technician A says that in a parallel circuit, a shorted resistor shorts out the entire circuit. Technician B says this can burn out the power supply unless the circuit is protected by a fuse or a circuit breaker. Who is correct?

Technician A only

Technician B only

both Technician A and Technician B

neither Technician A nor Technician B

306)Consider the circuit in Figure 1. The known voltages and currents are as indicated. Applying Kirchhoff's voltage and current laws, the value of the voltage drop across R2 would be:

60 V

50 V

20 V

40 V

307)Consider the circuit in Figure 2. The known voltages and currents are as indicated. Applying Kirchhoff's voltage and current laws, answer the following question. The value of the applied voltage source would be:

28 V

36 V

24 V

9 V

308)The value of the voltage drop across R4 Figure 2 would be:

24 V

9 V

16 V

12 V

309)The value of the current flow through R1 Figure 2 would be:

9 mA

6 mA

1.5 mA

15 mA

310).Answer the following question with reference to the series-parallel circuit in Figure 3.

10 Ohm

15 Ohm

22.5 Ohm

31 Ohm

311)The total power dissipated by the circuit in Figure 3 is:

1440 W

240 W

360 mW

240 mW

312)The total current flow of the circuit in Figure 4 is:

1.33 mA

1.5 mA

12 mA

2 mA

313)The total current flow of the circuit in Figure 5 is:

9 A

30 A

10 A

1.5 A

314)The current flow through resistor R2 in Figure 5 is:

2 A

1 A

6 A

8 A

315)If resistor R1 in Figure 5 becomes short-circuited, the total resistance of the circuit will:

increase.

decrease.

be infinite.

be zero.

316)Three substances that are classified as magnetic materials are:

aluminum, steel, and copper.

gold, silver, and nickel.

steel, nickel, and cobalt.

wood, paper, and glass.

317)The lodestone is a natural form of a:

temporary magnet.

permanent magnet

soft magnet.

heavy magnet.

318)Soft iron is most suitable for use in a:

permanent magnet.

natural magnet.

temporary magnet.

magneto.

319)Artificial magnets can be produced by:

a.placing a nonmagnetic material in the core of a coil and applying an AC voltage of the coil.

placing magnetic material in the core of a coil and applying a DC voltage to the coil.

placing a magnetic material in the core of a coil and applying an AC voltage to the coil.

placing a nonmagnetic material in the core of a coil and applying a DC voltage of the coil.

320)The magnetic force between two poles:

is measured using a galvanometer.

is measured using a multimeter.

increases as the distance between the two poles decreases.

decreases as the distance between the two poles decreases.

321)Permanent horseshoe-shaped magnets:

retain their magnetism longer than the bar type.

will not retain their magnetism as well as the bar type.

will not provide as strong a magnetic field as a bar magnet.

provide a much stronger magnetic field than a bar magnet of equal material.

322)A permanent ring magnet:

acts like two horseshoe magnets.

acts like two horseshoe magnets placed together with opposite poles touching.

has no designated poles.

both b and c

323)A material that acts as an insulator for magnetic flux is:

glass.

aluminum.

soft iron

unknown today

324)Which of the following is not assumed to be a characteristic of magnetic lines of force?

They travel most easily through air.

They form closed loops.

They repel each other.

They exit at the magnet's N-pole and enter at its S-pole.

325)Which of these does not normally have a demagnetizing effect?

DC applied to a coil

AC applied to a coil

heat

mechanical vibration

326)A DC current flow through a conductor will produce:

a magnetic field that acts in a clockwise direction.

a magnetic field that acts in a counter-clockwise direction.

a magnetic field that varies in direction.

either a or b

327)The left-hand conductor rule is used for a current-carrying conductor to determine the:

a direction of the lines of force around the current-carrying conductor.

south pole of the magnet by the direction of the thumb.

flux density of a magnetic field.

direction of rotation of the poles.

328)Lines of force of two parallel conductors with current flows in opposite directions will:

oppose each other to produce a weaker field.

aid each other to produce a stronger field.

tend to move together.

both a and c

329)If the electromagnet is operated with direct current, the polarity of its magnetic poles:

remains fixed.

constantly reverses.

is not affected by the polarity of the DC voltage source.

both b and c

330)The advantage of a toroidal core over a straight core is that the toroid is:

self-shielding.

cheaper to operate.

more compact.

easier to mount.

331)If other factors remain constant, which of the following combinations of electric current and the number of turns in the coil produces the strongest electromagnet?

500 turns and 2 A

700 turns and 2 A

300 turns and 4 A

100 turns and 10 A

332)The magnetic circuit consists of:

electrons traveling from the negative to the positive terminal.

molecular magnets traveling from the north pole to the south pole.

electrons spinning in the same direction.

lines of force travelling from the N pole to the S pole.

333)Consider the following changes made to an electromagnet: (i) increasing the number of turns in the coil; (ii) using a copper core instead of an iron core; (iii) decreasing the current flow in the coil. The strength of the electromagnet is increased by:

(i) only.

(ii) only.

(iii) only.

(i) and (ii) only.

334)A solenoid can be classified as an electromagnet with:

an air core.

a copper core.

moveable brass core.

a moveable iron core.

335)Solenoids can be used to operate:

valves.

latches.

switches.

all of these

336)Generating stations are classified according to:

the type of voltage generated.

their location.

the method used to drive their generators.

high voltage or low voltage.

337)The cheapest and most environmentally-safe type of generating station is:

a hydroelectric generating station.

a nuclear power generating station.

a coal power generating station.

a natural gas power generating station.

338)Which of the following converts the sun's energy directly into electrical energy?

steam turbine

water turbine

wind turbine

silicon wafer

339)Transmitting electrical energy from the generating station to the consumer usually takes place at:

very high AC-voltage levels.

very high DC-voltage levels.

very low AC-voltage levels.

very low DC-voltage levels.

340)Electrical transmission power-line losses are kept to a minimum by:

using large-diameter conductors.

using a high voltage and a low current.

using a low voltage and a high current.

both a and c

341)The unit used to measure electric power is:

the volt.

the ampere.

the watt.

the watthour.

342)When a 12-V battery delivers 18.0 A of current the power supplied is:

180 kW.

180 W

1.25 W.

216 W.

343)What is the power rating of an electric dryer element which has a resistance of 7.2 Ohm and is rated for 240 V?

1728 W

33.3 kW

7200 kW

17.28 kW

344)A wattmeter is connected:

in series with the load.

in parallel with the load.

with the ammeter section in parallel and the voltmeter section in series with the load.

with the ammeter section in series and the voltmeter section in parallel with the load.

345)A wattmeter is connected into a circuit and the pointer moves in the reverse direction. The problem can be corrected by:

reversing the two voltmeter leads.

reversing the two ammeter leads.

reversing both the voltmeter and ammeter leads.

either a or b

346)Technician A says electric energy is measured in joules. Technician B says it is measured in kilowatthours. Who is correct?

Technician A only

Technician B only

both Technician A and Technician B

neither Technician A nor Technician B

347)An electric lamp transforms electric energy into:

chemical energy.

light energy.

heat energy.

both b and c

348)How much energy is consumed when a 2000-W electric device is left on for 1 h?

2 kJ

2000 kJ

2000 kWh

2 kWh

349)The amount of electric energy used for electric appliances depends on:

the physical size of the appliance.

the length of time the appliance is used.

the amount of electric power required to make the appliance operate.

both b and c

350)Which of the following electric devices has, on an average, the highest annual energy consumption?

a range

a clothes dryer

a dishwasher

an air conditioner

351)Alternating current is current that:

operates from a voltage source that has a fixed polarity.

operates from a voltage source that has a constantly reversing polarity.

flows from negative to positive.

flows from positive to negative.

352)Generating a voltage by rotating a coil at a constant rate through a magnetic field results in a voltage that:

varies in magnitude.

varies in polarity.

varies in frequency.

both a and b

353)The standard frequency of the AC voltage available from the electric outlet in your home is:

220 V

50 V

50 Hz

220 Hz

354)If a sine wave has a peak-to-peak voltage value of 60 V, what is the rms value?

0 V

21.2 V

37 V

74 V

355)If a sine wave has a peak value of 220 V, what is the rms value?

672 V

311 V

155 V

77 V

356)For any given generator the output voltage varies:

directly with its speed and the strength of the magnetic field.

inversely with its speed and the strength of the magnetic field.

directly with its speed and inversely with the strength of the magnetic field.

directly with the strength of the magnetic field and inversely with its speed.

357)In an automobile alternator the three-phase AC stator voltage is converted to DC using:

slip rings.

diodes

a commutator.

a regulator.

358)The value of inductance is expressed in ohms.

True

False

359)In AC circuits the ohmic value of resistive elements depends on the frequency of the AC.

True

False

360)A resistance of 6in series with 14of reactance results in an impedance of 20.

True

False

361)The capacitive voltage can be higher than the source voltage is a series RLC circuit.

True

False

362)The cut-off frequency determines if the filter is a low-pass or high-pass filter.

True

False

363)The total opposition to current flow in an AC circuit is called :

Capacitance

Resistance

Impedance

Resonance

364)The true power in a resistance is measured in :

Ohms

Watts

Volts

Amperes

365)In a series resonant band-pass filter where: fr = 100 Hz, f1 = 95 Hz, f2 = 105 Hz, the bandwidth is _____.

10 Hz

10 kHz

200 Hz

20 Hz

366)A series RLC circuit is _____ when XL is greater than XC.

resonant

capacitive

inductive

none of the above

367)When a Norton equivalent circuit is converted to Thevenin equivalent circuit RTH will be equal to RN.

True

False

368)A Thevenin equivalent circuit represents an ideal (constant) voltage source.

True

False

369)When VRL for many values of VL must be determined, a circuit should be thevenized.

True

False

370)Current is independent of load resistance for a current source.

True

False

371)Norton's theorem reduces a resistive network to an ideal current source and a parallel resistance.

True

False

372)If two currents are in opposing directions through a branch of a circuit, the direction of the net current will be the same as that of the smaller current.

True

False

373)What is the Norton resistance as viewed by RL for the circuit below?

3 Ohm

6 A

0.5 A

5 V

374)Find the Thevenin resistance, as viewed by RL, for the circuit drawn below.

30 Ohm

30 V

25 Ohm

25 V

375)Find the Thevenin voltage, as viewed by RL, for the circuit drawn below.

30 Ohm

30 V

25 Ohm

25 V

376)What is the Norton current as viewed by RL for the circuit below?

3 Ohm

6 A

0.5 A

5 V

377)A trilight or dual filament lamp is rated for 40-60-100 W. This bulb would contain:

one 40-W and one 60-W filament.

one 100-W and one 50-W filament.

two 50-W filaments.

two 75-W filaments.

378)The best way to test an incandescent lamp filament is:

to shake it.

to check it for continuity with an ohmmeter.

to check it for voltage with a voltmeter.

to visually inspect it.

379)The resistance of a 200-W, 120-V incandescent lamp would be:

higher than that of a 40-W, 120-V incandescent lamp.

lower than that of a 40-W, 120-V incandescent lamp.

the same as that of a 40-W, 120-V incandescent lamp.

30 Q.

380)Recessed ceiling fixtures require special installation safety procedures because:

they operate at higher current values.

they operate at higher voltage values.

they have very poor ventilation.

they can become grounded very easily.

381)Which of the following is not an advantage of fluorescent lamps over the incandescent types?

lower initial cost

produce less heat during normal operation

produce more light per watt of power consumed

will last longer

382)The fluorescent bulb produces light by:

heating a filament to a white-heat temperature.

means of a chemical reaction within the tube.

means of an electron arc established between two cathodes.

means of magnet induction between two electrodes.

383)The instant-start fluorescent tube:

has a single-pin connection at each end.

requires a very high starting voltage.

requires a bulkier and more expensive type of ballast.

all of these

384)A cycling ballast that turns power OFF and ON is most likely caused by:

an overheated ballast.

the fixture not being adequately grounded.

the tube pins making power contact.

the line voltage being too low.

385)Which of the following is not an advantage of high-intensity discharge lamps?

They operate at low current.

They have a very long life expectancy.

They have a high light efficiency.

They have a high watt output from a single fixture.

386)High-intensity discharge lamps:

operate without the use of a ballast.

operate ON and OFF very quickly.

operate at low brightness when first turned on.

both a and c

387)In an ideal inductor:

current lags the voltage by 90?.

current leads the voltage by 90?.

current lags the voltage by 180?.

current leads the voltage by 180?.

388)Energy is stored in a capacitor by means of:

its electrolytic field.

its force field.

its magnetic field.

its electrostatic field.

389)As applied to a capacitor, the word dielectric refers to:

the conducting material of the capacitor.

the metal used as the plate.

the insulating material separating the plates.

the capacitance of the capacitor.

390)Polarized fixed capacitors must be connected:

in series only.

in parallel only.

with the positive lead of the capacitor connected to the positive lead of the circuit.

with the negative lead of the capacitor connected to the positive lead of the circuit.

391)Which indication on an ohmmeter should you most likely expect when testing a good capacitor?

no pointer deflection at all

momentary upscale pointer deflection

full-scale deflection of pointer

midscale indication

392)Approximately what percentage of the applied voltage does the capacitor charge to at the end of the first time constant?

70 percent

63 percent

33 percent

15 percent

393)A 50- F capacitor is connected to a 120-V, 60-Hz source. The capacitive reactance of this capacitor would be approximately ____ ohms.

2650

265

53

2.65

394)In general, impedance has an effect on an AC circuit similar to:

frequency.

voltage.

current.

resistance.

395)Impedance may be defined as:

the total opposition to current flow in an AC circuit.

the total opposition to current flow in a DC circuit.

the total opposition offered by a capacitor to alternating current flow.

the total opposition offered by an inductor to alternating current flow.

396)Lagging power factor is often produced by:

fluorescent lamp ballasts.

induction motor windings.

solenoid coils in relays.

all of these

397)A transformer is a device used to:

rectify voltages from AC to DC.

transfer electric energy by mutual induction.

convert mechanical energy into electric energy.

all of these

398)An iron core is used in a transformer to:

reduce hysteresis loss.

eliminate eddy current losses.

ensure good magnetic linkage between windings.

reduce the counter-emf.

399)A step-down transformer is used to change:

high power to low power.

alternating current to direct current.

high voltage to low voltage.

high current to low current.

400)The transformer used with a certain model car set has 240 turns in its primary coil and 24 turns in its secondary coil. If the transformer is connected to a 120-V wall receptacle the secondary voltage output would be approximately:

6-V AC.

12-V AC.

18-V AC.

24-V AC.

401)Most transformers operate to transfer energy at an efficiency of about:

25 percent.

75 percent.

80 percent.

95 percent.

402)A certain transformer has a turns ratio of 1:1. The transformer is used for:

impedance matching.

changing frequency.

isolation.

stepping-up voltage.

403)Power transformers are designed to operate:

from 60-Hz line frequency.

in the audio frequency range.

in the radio frequency range.

all of these

404)Which of these would most likely be used to match a 4- speaker to a 400-- amplifier output?

audio impedance-matching resistor

IF transformer

current transformer

auto transformer

405)A transformer coil can be checked with an ohmmeter for:

continuity.

eddy currents.

overloads.

overheating.

406)The rated input and output voltages of a transformer are checked with a voltmeter. Technician A says a normal primary voltage reading and no secondary voltage reading is an indication of an open secondary coil. Technician B says it is normal for the transformer output voltage to be higher than specified if no load is connected to the output. Who is correct?

Technician A only

Technician B only

both Technician A and Technician B

neither Technician A nor Technician B

407)The purpose of a power supply is:

to amplify weak signals.

to rectify weak signals.

to convert the electrical input voltage to the proper type and value needed to operate circuits.

all of these

408)In a power-supply circuit the transformer can be used to:

step up voltages.

electrically isolate circuits.

supply a variable AC voltage.

all of these

409)A step-down transformer will have:

more turns on the secondary than on the primary.

a higher primary than secondary voltage.

a higher primary than secondary current.

all of these

410)A step-up transformer will have:

less turns on the primary than on the secondary.

a higher secondary than primary voltage.

a lower secondary than primary current.

all of these

411)A standard transformer can safely isolate a 120-V primary circuit from a 10-V secondary circuit because:

the primary and secondary coils are connected in parallel with each other.

no physical electrical connection exists between the primary and secondary coils.

the primary and secondary coils are connected in series with each other.

the primary and secondary coils are connected so as to lower the input voltage.

412)What is the output ripple frequency of a bridge rectifier?

one-half the input frequency

twice the input frequency

the same as the input frequency

one-fourth the input frequency.

413)The approximate DC voltage output of a full-wave rectifier is equal to:

the rms value of the peak output value.

the peak value of the output voltage.

0.318 of the peak output voltage.

0.637 of the peak output voltage.

414)Which of the following components is commonly used as a filter device?

a transformer

a resistor

a capacitor

a diode

415)Increasing the capacitance of the filter capacitor will have what effect on the ripple amplitude?

ripple will increase

ripple will remain the same

ripple will double

ripple will decrease

416)The voltage regulation of a power supply refers to:

the rules applied when wiring it.

the specifications of the components used in wiring it.

the ability of a power supply to maintain a constant output voltage.

the ability of a power supply to withstand overloads.

417)Voltage and current are in phase when the load contains:

nothing but reactance

nothing but resistance

neither of the above

both of the above

418)Current and voltage will be 90 degrees out of phase when the load contains:

nothing but reactance

nothing but resistance

neither of the above

both of the above

419)The magnitude and direction of an electrical quantity can be shown with:

a victor

a pure number

neither of the above

both of the above

420)Power is used by the

resistive part of a load

reactive part of the load

all parts of the load

none of the above

421)The unit for apparent power is the:

apparent watt

apparent joule

apparent dissipation

voltampere

422)Current will lead voltage by 90 degrees when the load is:

pure capacitance

pure inductance

both inductance and resistance

none of the above

423)The numerical value of the cos O when the load contains only resistance is:

zero

0.707

one

infinite

424)When the PF = 90%, the cos O is:

one

0.988

0.900

unknown

425)When P = 500 W, I = 6 A, and V = 120 V, the PF will be:

greater than 1.0

negative

unknown

0.69

426)When I = 4 A, P =300 W, and V= 240 V, angle theta will be:

71.8grd

77.0grd

0.77grd

3.2grd

427)A capacitor consists of two conductive plates separated by a(n):

dielectric

insulator

neither of the above

both of the above

428)The base unit of capacitance is the:

farad

tesla

ohm

none of the above

429)Most electrolytic capacitors are:

ac capacitors

very high Q capacitors

polarized capacitors

none of the above

430)The relative energy loss of a capacitor is specified by its:

quality rating

power factor rating

dissipation factor rating

any of the above

431)In one time constant, a capacitor charges to:

the source voltage

63.2 % of the source voltage

63.2 % of the available voltage

none of the above

432)In the circuit below, VC2 will be:

20 V

25 V

80 V

none of the above

433)CT for the circuit in question 6 will be:

5 uF

1.25 uF

0.8 uF

none of the above

434)The reactance of a 0.022-uF capacitor at 500 Hz will be:

69 Ohm

14.5 mOhm

1450 Ohm

none of the above

435)For the circuit below, XCT will be:

1592 Ohm

796 Ohm

318 Ohm

531 Ohm

436)The energy stored in a 200