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