EE Flashcards
(128 cards)
1
Q
A property ascribed to phenomena, bodies or substances that can be quantified for, or assigned to a particular phenomenon, body, or substance.
A
Quantity
2
Q
A quantity that can be used in the mathematical equations of science and technology
A
Physical Quantity
3
Q
A particular physical quantity defined and adopted by convention, with which other particular quantities of the same kind are compared to express their value
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Unit
4
Q
The smallest portion into which an element can be subdivided without losing its physical and chemical properties
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Atom
5
Q
If an object contains more number of total electrons than the total protons
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Negatively charged
6
Q
If an atom contains of fewer number of electrons than the number of electrons
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Positively charged
7
Q
Amount of electrical charge on a single electron
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Elementary Charge Unit (ECU)
8
Q
Used to measure quantity of electric charge; approximately equal to 6.24 x 10^18 ECU
A
Coulomb (C)
9
Q
The result of non-random movement of electrons
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Current
10
Q
Defined as the rate of electrical charge flow
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Current (I)
11
Q
Causes electric charge to flow in an electrical system having potential difference
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Electromotive force and potential difference
12
Q
The ability of a material to resist the flow of electrical charge when subjected to a given potential difference
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Electrical Resistance
13
Q
Property of materials to oppose the flow of electric current
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Resistivity
14
Q
Material which has low resistance to electron flow
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Conductors
15
Q
Material which has high resistance to electron flow
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Insulators
16
Q
Materials having an intermediate resistance to electron flow; usually used in construction of solid state electronic devices such as diodes and transistors.
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Semi conductors
17
Q
reciprocal of resistance, measured in mhos
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conductance
18
Q
ability of materials to conduct electricity
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conductivity
19
Q
a phenomenon when conductors lose their resistance in extreme cold
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superconductivity
20
Q
components are connected end-to-end in a line to form a single path for electrons to flow
A
series connection
21
Q
all components share the same (equal) current
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series connection
22
Q
all components are connected between the same set of electrically common points
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parallel connection
23
Q
all components share the same (equal) voltage
A
parallel connection
24
Q
measured in farad (F)
A
capacitance
25
the concept is closely related resistors connected in series
Voltage divider
26
the voltage across each resistors is _________ to the ratio of its resistance to the total series resistance of the circuit
directly proportional
27
the concept is closely related to resistors in parallel
current divider
28
the current divides in ______ to the resistances of the individual parallel elements
inverse proportion
29
it is always possible to view a very complicated circuit in terms of much simpler equivalent source and load circuits
Equivalent Circuits
30
from the point of view of the load, any network composed of ideal voltage and current sources, and of linear resistors, maybe presented by an equivalent circuit consisting of an ideal voltage source in series with an equivalent resistance
Thevenin's Theorem
31
from the point of view of the load, any network composed of ideal voltage and current sources, and of linear resistors, maybe presented by an equivalent circuit consisting of an ideal current source in parallel with an equivalent resistance
Norton's Theorem
32
States that the current flowing in a circuit varies directly with electrical pressure and inversely with opposition
Ohm's Law
33
in kirchoff's voltage law, the sum of the voltage around a closed path is equal to _______
zero
34
in a closed path, the sum of the voltage rise is equal to the voltage drop
kirchoff's voltage law
35
because charge cannot be created but must be conserved, the sum of the currents entering a node is equal to the sum of the currents leaving the node
kirchoff's current law
36
an instrument that gives a reading of the product of the current and the voltage in a circuit
wattmeter
37
the value of the power factor depends on the kin of opposition offered. It is never ______ than 1
greater
38
for heaters, incandescent lamps and electric ranges, power factor is ____ to 1
equal
39
for electric motors, power factor ranges between _____
0.6 to 0.8
40
it is power expended or used over a period of time
energy
41
common unit of electric power is_____
watt
42
common unit of electric energy consumption is ____
watt-hour
43
this type of meter is used for billing customers for electric usage
kilowatt-hour meter
44
characterized by non-variant current flow in one direction at all times
direct current (DC)
45
characterized by an alternating flow of current in two directions
alternating current (AC)
46
a plat of values of quantities which vary with time
waveform
47
signal that repeats the same shape at regular intervals of time
periodic waveform
48
the magnitude of a waveform at any instant of time
instantaneous value
49
the maximum instantaneous value of a function from zero-volt level
Peak Value
50
the sum of the magnitudes of the positive and negative peaks
peak-to-peak value
51
the time interval between successive repetitions of a periodic waveform
period
52
the portion of a waveform contained in one period of time
cycle
53
the number of cycle that occur in one second
frequency
54
the area under curve over a period of time
average value
55
the effective value that would produce the same effect as an equivalent direct current
root-mean-square value
RMS value
56
when voltage and current are in phase, all power is ____
positive
57
when circuit contains elements with other than pure resistance (capacitance or inductance), phase shift will occur between ____
voltage and current waves
58
the property to oppose current change
inductance
59
the amount of electric charge that a capacitor receives for each volt of applied potential
capacitance
60
the angle between the pure resistance and the total impedance is_____
phase shift angle
61
current in AC circuit with pure inductance will lag the voltage by ____
90 degrees
62
in an AC circuit with pure capacitance loading the current will lead the voltage by____
90 degrees
63
the optimum situation for transmission of power exists when the power factor of the load equals unit, that is , when the phase shift angle is _____
0 degree or zero
64
the quantity of magnetic field force or push
magnetomotive force (mmf)
65
also known as magnetic potential difference
magnetomotive force (mmf)
66
quantity of total field effect or "substance" of the field
magnetic flux
67
analogous to electric voltage (emf)
magnetomotive force (mmf)
68
analogous to electric current
magnetic flux
69
amount of field force (mmf) distributed over the length of the electromagnetic
Magnetic field strength
70
amount of magnetic field flux concentrated in a given area
magnetic flux density
71
opposition of magnetic field flux through a given volume of space or material
reluctance
72
analogous to electrical resistance
reluctance
73
specific measure of material's acceptance of magnetic flux,
permeability
74
describes that the electric field due to electric charges can be derived by coulomb's law
Gauss's Law for electricity
75
states that the net magnetic flu through any (real or imaginary) closed surface is zero
Gauss's Law for Magnetism
76
describes the production of magnetic fields not only by electric currents but by changing electric field as well
Ampere's Law
77
describes the production of electric fields as a result of changing magnetic fields
Faraday's Law of Induction
78
voltage induced by changing magnetic flux
induced electric voltage
79
current produced during electromagnetic flux
induced current
80
factors which controls the magnitude of the induced votage
SLAS
S-strength of the magnetic field
L-length of the conductor within the field
A-angle at which the conductor passes through the field
S-speed at which the conductor passes through the field
81
3 standard types of DC generators
SSC
S-shunt generator
S-series generator
C-compound generator
82
3 general classes of synchronous generators
slow-speed-engine-driven type
moderate-speed-waterwheel-driven type
high-speed-turbine-driven type
83
slow-speed-engine-driven type (rpm?)
75-90 rpm
84
moderate-speed-waterwheel-driven type (rpm?)
80-900 rpm
85
high-speed-turbine-driven type (rpm?)
720-3600 rpm
86
Motor torque at zero speed or the maximum torque available to start the load
Locked-rotor torque
87
Lowest value of torque produced by the motor between zero and full load
Pull-up Torque
88
torque necessary to produce the motor's rated horsepower at rated speed
full-load torque
89
maximum torque a motor can carry without an abrupt drop in speed that may make the motor stall or inoperative
breakdown torque
90
torque available for acceleration
acceleration torque
91
refers to how frequently the motor is started and for how long it will run each time it is started
duty ratingi
92
desirable for motors operating in clean air and water is kept away from entering the motor
open-type enclosure
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fins are constructed on the frame not affected by dusty condition and water splashes
closed-type enclosure
94
desirable for motors operating in wet condition such as in pumping
drip-proof type enclosure
95
indicates the maximum load that can be successfully carried by the motor if it is to operate continuously and remain a safe temperature range
service factor
96
mechanical output can be measured either with _________
dynamometer or prony brake test
97
electrical input can be measured by __________
voltmeter, ammeter, and wattmeter
98
motors performs best at rated voltages, therefore wire must be sized to avoid voltage drop (allowable voltage drop is____
less than or equal to 2%
99
branch circuit conductors to individual motors should be selected to carry _______ of full load current of the motor to allow for a certain degree of overload
125%
100
6 primary methods of producing electrical energy
```
friction
pressure
heat
chemical reaction
light
magnetism
```
101
a device that transfer energy from one electric circuit to another without change in frequency
Transformer
102
the primary winding has more turns than the secondary
step-up transformer
103
the primary winding has fewer turns than the secondary
step-down transformer
104
electrical conductors which are 8 mm^2 (AWG NO. 8) or smaller in size
wires
105
larger than wires.
cables
106
the term given to an insulated stranded wire
cord
107
pipe that encloses and protects wire and cables
conduit (raceway)
108
combined terms of ampere and capacity;
ampacity
109
expresses the current-carrying capacity of wire and cables
ampacity
110
provide access points for pulling and feeding conductors into a raceway system
Junction and pull boxes
111
a unit area equal to that of a circle whose diameter is 1 mil (0.001)
circular mil
112
typically plastic resins, soften and flow when they are heated and subjected to pressure , but they become rigid when cooled
thermoplastic
113
initially set or cure when heated, but after curing they will soften, flow or distort
thermoset
114
insulation code R
thermoset
115
insulation code T
thermoplastic
116
insulation code X
cross-linked polyethylene thermoset
117
maximum temperature code H
75 degree Celcius
118
maximum temperature code HH
90 Degree Celsius
119
maximum temperature code nothing
60 degree celcius
120
Designed to resist the flow of current
Resistors
121
Devices that increases potential difference for current flow
Voltage sources
122
Devices that store energy in an electrostatic field
Capacitor
123
Devices that store energy in a magnetic field
Inductors
124
Devices that acts as a one way switch. Allowing the current to flow in one direction only
Diode
125
amplifies signals
Transistors
126
In kirchoffs law, the algebraic sum of current at any node is equal to ____
Zero
127
In kirchoffs law, the sum of currents entering is _____ to the sum leaving
Equal
128
Materials that permits electrons to move freely are called _____
Conductors
