問題一覧
1
__ is the production of current flow due to a magnetic field on a coil
inductance
2
A __ Is a three – terminal semiconductor, switch – like device that controls current according to the amount of voltage applied to the base
Transistor
3
A(n) ___ Consists of two sets of windings wrapped around an iron or laminated steel core
transformer
4
Combustion power generation plants use steam to produce electricity
True
5
A _ Circuit is a circuit that has two or more components connected so that there is one path for current to flow
series
6
Voltage interruptions may Be momentary, temporary, or ____
sustained
7
In general, the higher, the current flow, the higher amount of work performed by the circuit
True
8
A(n) _ Power plant is a power plant that generates both electricity and heat for use
cogeneration
9
___ is the energy produced from the flow of electrons through a conductor
Electricity
10
Diodes are used for rectification and to block current flow
True
11
Line voltage is voltage at 115 VAC to 1000 VAC
False
12
___ Voltage is voltage of 50 VAC or less
low
13
A(n) __ Transformer has a higher output voltage than input voltage
step up
14
A solid – state relay is a switching device that has sets of contacts that are closed by a magnetic force
False
15
____ is the amount of electrical pressure in a conductor
voltage
16
__ is the amount of electrons flowing through a conductor
current
17
A(n) ___ is a type of thyristor that is capable of only switching direct current
silicon controlled rectifier
18
Alternating current is current the reverses direction at regular intervals
True
19
A cogeneration power plant is a power plant that changes energy from moving water into electrical energy.
False
20
The most common material used for a semiconductor device is silicon
True
21
A _ Is a switch that isolates electrical circuits from a voltage source to allow safe access into electrical panel or equipment for maintenance or repair
Disconnect
22
___ law expresses the relationship between voltage, current and resistance, and a circuit
Ohm’s
23
A _ Is a type of semiconductor device that allows current to flow in one direction only
diode
24
A transient voltage is a temporary unwanted voltage that ranges from a few volts to several thousand volts and less from a few microseconds to a few milliseconds
True
25
A __ transformer has a lower output voltage than input voltage
Step – down
26
Alternating current (AC) is current that flows in one direction only.
False
27
__ are power frequencies that are whole integer multiples of the base frequency (60 Hz)
harmonic
28
A(n) ___ Diode is a type of diode designed to operate in a reverse – biased mode without being damaged
zener
29
A _ Is an overcurrent protection device with a mechanism that automatically opens a circuit when an overload or short circuit occurs
Circuit breaker
30
A _ Is an electrical device that consist of two thin metal plates with an insulating dielectric material separating them
Capacitor
31
An insulator is a material with low resistance that permits electrons to flow through it easily.
False
32
A(n) _ Shut off the power supply to a circuit when current flow is excessive
Overcurrent protection device
33
A(n) __ transformer has the same number of primary and secondary turns in the windings
isolation
34
The most common type of wire used today is aluminum.
False
35
A _ Is a device that changes AC voltage into DC voltage
Rectifier
36
Electrical control system use AC voltage
True
37
__ is the international unit of frequency equal to one cycle per second
hertz
38
An electromechanical relay is a switching device That uses semiconductor materials to change on and off characteristics
False
39
A(n) ___ is a device that performs work
load
40
A(n) _ is the interconnection of conductors and electrical elements through which current is designed to flow
Electrical circuit
41
A semiconductor is a material in which electrical conductivity is between that of a conductor and that of an insulator
True
42
___ is the positive (+) or negative (-) state of an object
polarity
43
A _ Is a large heavy dash duty relay – like switching device that uses low-voltage to energize or De-energize the high-current nonmotor load connected to it
Contactor
44
AC voltage is either single phase or three phase
True
45
Transformers are classified as step up step down or isolation transformers
True
46
The opposition of current flow is called __
resistance
47
___ Energy is used to produce heating and cooling for residential commercial and industrial use
electrical
48
A _ Is an overcurrent protection device with a fusible link that melts and opens a circuit when a overload condition or short circuit occurs
Fuse
49
A(n) ___ is a solid – state switching device used to switch alternating current
triac
50
A(n) ___ diode Is a type of diode designed to produce light when forward – biased
light emitting
51
Transient voltages are often caused by lightning or stored voltages being released from __
capacitors
52
A__ circuit is a circuit that has two or more components connected so that there is more than one path for current to flow
parallel
53
Resistance is measured in ohms.
True
54
__ Is sine wave distortion from motors and electrical devices that enters a power distribution system directly on the wires/grounds or through the magnetic coupling of adjacent wires
noise
55
A(n) ___ Is an electronic device in which all devices, such as transistors, diode, and resistors, are contained in a single package or chip as components
integrated circuit
56
High voltage is voltage over 600 VAC
True
57
A(n) ___ Is a device that uses a low-voltage coil to close one or more sets of contacts to switch high voltage loads on and off
relay
58
A(n) _ Circuit is a combination of series – and parallel – connected components in a circuit
series parallel
59
Hydroelectric, power plans, solar, power, and wind power are __ sources of energy
renewable
60
A(n) ___ Is a type of diode that changes resistance, or switches on when exposed to light
photodiode
61
An electronic control system is a type of control system that uses solid-state devices to control refrigeration, and HVAC systems
True
62
A conductor is a material that resists the flow electrons.
False
63
The two most common voltages for electrical control systems are 24 VAC and 115 VAC
True
64
Triacs are used as solid-state relays
True