Electronics Information Flashcards
1
Q
Alternating current is so called because
A
the current changes direction many times per second
2
Q
An electric current is
A
a form of energy
a flow of electrons
3
Q
A battery
A
always produces a direct current
4
Q
In a series circuit, total voltage drop equals
A
the sum of the individual voltage drops
5
Q
A volt is a unit of electric(al)
A
pressure
6
Q
The transformor depends on the relationsip between electricty and
A
magnetism
7
Q
In an electric motor, magnets
A
repel each other
8
Q
A circuit without resistance is called
A
a short circuit
9
Q
A transformer changes the _______ in a circuit
A
current and voltage
10
Q
In a series circuit, a switch controls
A
all devices on the circuit
11
Q
Which is the same at all points in a parallel circuit
A
voltage
12
Q
A switch in a series-parallel circuit controls
A
some or all devices
13
Q
The purpose of dopant in a semiconductor is to make it act as a(n)
A
insulator or conductory
14
Q
Electricity
A
a form of energy that can travel invisibly
15
Q
Tiny negative charges that orbit the nucleus of an action
A
electrons
16
Q
Conductor
A
a material that allows an easy flow of electrons
17
Q
Good conductors
A
silver
copper
aluminum
18
Q
Material that resists the flow of electrons
A
insulator
19
Q
Good insulators
A
rubber
plastic
ceramic
20
Q
A loop of conductor that tkes electricity from it’s source to the load and back to the source
A
circuit
21
Q
Load
A
anything in the circuit such as a heater, a light, or motor that uses power
22
Q
Direrct current (DC)
A
a steady flowiwng type of electricity produced by batteries and used in flashlights, boom boxes and computers
23
Q
Alternating Current (AC)
A
type of current that changes direction many times per second (used in homes)
24
Q
A branch of science that deals with complicated uses of electricity, such as radios, televisions, and computers
A
electronics
25
Electric current
the amount of electrons flowing through a conducting material
26
Amount of power consumed by an electrical device
electric power
27
Voltage
force that afects the rate at which electricity flows through a conductor
28
Sometimes called electrical pressure
voltage
29
Tells how much electrical pressure is used in a part fo the circuit
voltage drop
30
Frequency
the number of complete alternations-from one direction to the other and then back again-that alternating current makes per second
31
The opposition of a material to the flow of electricity through it
resistance
32
If a circuit does not have resistance, wires can overheat, this is called
a short circuit
33
Ohm's law
describes the relationship among electircal pressure (voltage) current strength (amperage) and resistance (ohm's) in any circuit
34
Amperes =
volts/ohms
35
Volts =
amperes x ohms
36
Ohms =
volts/amperes
37
Electric power
watts = volts x amperes
38
Amperes =
watts/volts
39
If a transformer has more turns of wire on the output side it is a
step up transformer
40
In a stepdown transformer
there are more turns on the input side and the output voltage is smaller than the input voltage
41
The same machines operating backwards
motors and generators
42
Changes rotating energy (kinetic) into electric energy
a generator
43
Motor
changes electric energy into kinetic energy
44
What drives a motor
the changes in polarity
45
The two types of magnets in a motor
rotor and stator
46
Spins inside the stator
Rotor (usually an electromagnet)
47
Stator
stationary magnet
48
In motors which poles attract
opposite, north attracts south but repels north
49
A device that can briefly store electricity
a capacitor
50
A resistor
creates resistance to the flow of electrons
51
If a circuit does not have any resisitance it is called
a short circuit
52
Changes the voltage and amperage of a current
a transformer
53
Transformers work by
changing electricity into magnetism, then back into electricity
54
How many coils does a transformer have
2
55
Stores electricty as chemical energy that can be readily converted into electric current
a battery
56
Batteris can be wet (like car batteries) or dry (like flashlight batteries)
Batteris can be wet (like car batteries) or dry (like flashlight batteries)
57
Always make Direct current (DC)
batteries
58
Some batteries can be recharged depending on
their chemistry
59
What travels through a circut to make an electric current
electro chemiclal reactions between the cathode and the carbon electrode at the center, resulting in free electrons
60
Exists only when electon can flow through a circuit
electric current
61
What are the types of circuits
series circuits
| parallel circuits
62
All moving electrons pass through every part of the circuit including all the loads and swithches is a
series circuit
63
The quality of electrons
current
64
Is the same at all points of the circuit
current
65
Drops a sthe current goes through each device
voltage
66
The total voltage of the loads must equal the voltage of the
circuit
67
The loads are placed between the two supply wires so that they all get teh same voltage in a
parallel circuit
68
A switch controls the current in the entire circuit in a
Series circuit
69
Current can flow through only loads even if one is switched off in a
parallel circuit
70
Current is the same at all points in a
series circuit
71
Voltage is the same at all points in a
parallel circuit
72
How do you find total resistance in a series circuit
add teh resisitance of each load
73
To calculate the total resistance in a parallela circuit you
add the inveres of the reisitance
74
Combines features of series and parallel circuits
series-parallel circuit
75
The branch circuits that bring electric power to the lights and outlets are
series-parallel
76
Can act as a conductor or as an insulator
semiconductor
77
The main semiconductor that is the basis for computer memory and logic boards
silicon
78
Applied to silicon to determin whether it will act as an insulator or as a conductor by making electons available or not available to flow
dopants
79
When electrons can flow, a material becomes a
conductor
80
The basis for computer applications is a group of components called
transistors and diodes
81
Transistors
devices that can switch a current, regulate its flow, or amplify a current, all based on the prescence of a smaller current
82
Devices that allow a current to flow in one direction only
diodes
83
Diodes are also used in devices that convert AC into DC. These devices are called
rectifiers
84
Breaking up the load in the building into a number of circuits is a function of the
circuit breaker box
85
The circuit breaker box
prevents excess current from flowign into the circuits
| breaks up the load in the building into a number of circuits
86
Simple circuits have what two separate conductors
hot and grounded
87
The hot conductor can be another color but it is usually
black
88
The grounded (sometimes called neutral) conductor is
white
89
Black and white wires together are called
supply wires
90
circuits can be shut off by
the fuses and circuit breakers
91
Home wiring systems are usually rated
15 or 20 amperes
92
15 ampere circuits require
14 gauge wires
93
Larger 12 gauge wires are required for
20 ampere circuits
94
Always wants to complete a circuit
electricity
95
Two options for returning current to the circuit breaker or fuse box are
```
white wire (grounded) is the normal path
bare wire (equipment grounding) is the alternate path of something goes wrong with the grounded wire
```
96
Conduit
steel sheath or wires that protect bare wire
97
Brings current
black wire
98
Drains current away
white wire
99
Electric plugs that can fit into the socket in only one way because one lug on the plug is bigger than the other is called a
polarized plug
100
Turns electic circuits on and off
switches
101
One single-pole switch controls a circuit
One single-pole switch controls a circuit
102
Two three-way switches can work together to control a circuit from either fo two locations
such as at the top and bottom of a stairs
103
Continuously controls the voltage, and is used to dim lights
a rheostat
104
In home wiring switches alwasy control the hot side of the circuit
(the one that supplies the current)
105
If electrical connections are not secure and tight what will develop causing heat and ruining the connection
arcs will develop
106
Solder
a connection where metal is melted over a connection
107
Flux
a chemical that prevents oxidation from happening when wires get heated
108
Breaks the circuit (cuttng off the power) when something goes wrong is the job of the
circuit breakers and fuses
109
Usually has an electomagnet that opens a circuit when the current gets too high
a circuit breaker
110
Has an element that melts when the current is too high
fuse
111
Can be reset after they trip
circuit breakers
112
Coaxial
having the same axis
113
Cables that have an inner and outer conductor and are usually used in cable TV systems are called
coaxial cables
