MODULE2 - DC CIRCUITS Flashcards
Learn fundamentals of DC circuits (157 cards)
1
Q
Smallest amount of electrical charge having the quality called negative polarity
A
ELECTRONS
2
Q
(T/F) Protons orbit the center of atoms
A
FALSE
3
Q
a basic particle with positive polarity
A
PROTON
4
Q
Protons are located in the _____ of atoms along with neutrons, particles which have neutral polarity
A
NUCLEUS
5
Q
Electrical classification of all materials
A
CONDUCTORS, INSULATORS, SEMICONDUCTORS
6
Q
Materials in which electrons can move freely from atom to atom
A
CONDUCTORS
7
Q
CONDUCTORS have __ valence electron/s
A
1
8
Q
The purpose of conductors is to allow electrical current to flow with ________
A
minimum resistance
9
Q
(T/F) In general all metals are good conductors.
A
TRUE
10
Q
Have 8 valence electrons
A
INSULATORS
11
Q
Materials in which electrons tend to stay put and do not flow easily from atom to atom are termed
A
INSULATORS
12
Q
(T/F) Insulators are used to prevent the flow of electricity.
A
TRUE
13
Q
are used in components like capacitors which must store electric charges
A
DIELECTRICS
14
Q
examples of dielectrics
A
glass, rubber, plastics
15
Q
SEMICONDUCTORS have ___ valence electrons
A
4
16
Q
Materials which are neither conductors nor insulators
A
SEMICONDUCTORS
17
Q
Used in components like transistors
A
SEMICONDUCTOR
18
Q
Example of semiconductor
A
CARBON, GERMANIUM, SILICON
19
Q
The symbol for charge is Q which stands for ____
A
QUANTITY
20
Q
The practical unit of charge is called the
A
COULOMB
21
Q
One coulomb is equal to the amount of charge of ___ electrons or protons stored in a dielectric
A
6.25X10^18
22
Q
The fundamental electric quantity
A
CHARGE
23
Q
The smallest amount of charge that exists is carried by
A
ELECTRON AND PROTON
24
Q
Atoms are composed of charge carrying particles: electrons and protons, and neutral particles, ____.
A
NEUTRONS
25
CHARGE OF PROTON
qp = 1.602x10^-19 C
26
Charge of an electron
qe = -1.602x10^-19 C
27
(T/F) In semiconductors - free electrons can be forced to move with relative ease, since they require little work to be moved.
FALSE
28
Charge in motion
CURRENT
29
(T/F) The more electrons in motion the greater the current
TRUE
30
When a charge is forced to move because of a ____ current is produced
POTENTIAL DIFFERENCE/VOLTAGE
31
indicates the intensity of the electricity in motion
CURRENT
32
The symbol for current is I which means
INTENSITY
33
Current is measured in
AMPERES
34
The definition of current is:
I = Q/T
35
1 ampere is
1 coulomb per second
36
Current moves through a circuit element
"THROUGH VARIABLE"
37
____ is rate of flow of negatively-charged particles, called electrons, through a predetermined cross-sectional area in a conductor.
CURRENT
38
refers to the the possibility of doing work
POTENTIAL
39
Any charge has the potential to do the work of attracting a similar charge or ____ an opposite charge.
REPULSING
40
The symbol for potential difference is E which means
ELECTROMOTIVE FORCE
41
The practical unit of potential difference is
VOLT
42
is a measure of the amount of work required to move 1C of charge
1 VOLT
43
Potential difference across two terminals in a circuit _____
ACROSS VARIABLE
44
Each cell provides 1.5 V
| Three cells connected one after another, in series, would provide ___
4.5V
45
(T/F) If the cells are connected in parallel, the voltage stays the same, but now a larger current can be drawn.
TRUE
46
Opposition to the flow of current is termed
RESISTANCE
47
The fact that a wire can become hot from the flow of current is evidence of
RESISTANCE
48
Conductors have ___ resistance.
VERY LITTLE
49
Insulators have ____ of resistance.
LARGE AMOUNT
50
The practical unit of resistance is
OHM
51
ohm is designated by the Greek letter __
OMEGA
52
an electronic component designed specifically to provide resistance
RESISTOR
53
defined as a path for current flow
CIRCUIT
54
In applications requiring the use of current, electrical components are arranged in the form of a
CIRCUIT
55
An open circuit has
INFINITE RESISTANCE
56
where the energy of the source (battery) is carried by means of the current through the the various components.
CIRCUIT
57
The circuit components are the ____ - they determines how much current the source will produce.
LOAD RESISTANCE
58
The battery is the ____, since it provides the potential energy to be used.
SOURCE
59
The direction of electron flow in our circuit is from the ____ side of the battery, through the load resistance, back to the _____ side of the battery.
NEGATIVE, POSITIVE
60
Inside the battery, electrons move to the negative terminal due to ______, maintaining the potential across the leads.
CHEMICAL ACTION
61
Circuits that are powered by battery sources are termed
DIRECT CURRENT CIRCUITS
62
In DC circuits, the battery maintains the ____ of output voltage. The plus and minus sides remain constant.
SAME POLARITY
63
CHARACTERISTICS OF DC
It is the flow of charges in just one direction and...
| The fixed polarity of the applied voltage which are characteristics of DC circuits
64
periodically alternates or reverses in polarity.
ALTERNATING VOLTAGE SOURCE
65
The power outlet in your home is ___ cycle ac - meaning the voltage polarity and current direction go through ___ cycles of reversal per second.
60
66
(T/F) All audio signals are AC
TRUE
67
(T/F) Heating Effects the same for both AC and DC current
TRUE
68
DC is used as ____ for tube and transistor amps
ELECTRODE VOLTAGE
69
AC is used as ____ for tube and transistor amps
I/O SIGNAL
70
DC is easier to
MEASURE
71
AC is easier to
AMPLIFY
72
(T/F) DC circuits are usually simpler than AC circuits.
TRUE
73
(T/F) However, the principles of DC circuits DO NOT apply to AC circuits.
FALSE
74
is resistance to current flow in AC circuits
IMPEDANCE
75
Symbol of impedance
Z
76
Impedance is measured in
OHMS
77
One side of the voltage source is usually ___ for safety
GROUNDED
78
For 120 V - ac power lines in homes this means one side of the voltage source is connected to a ___.
METAL COLD WATER PIPE
79
For electronic equipment, the ground just indicates a ____, which is used as a _____ for connections to the source.
METAL CHASSIS, COMMON RETURN
80
The amount of current in a circuit is dependent on its resistance and the applied voltage. Specifically I = E/R
OHM'S LAW
81
Current is ___ Proportional to Voltage for a Constant Resistance
DIRECTLY
82
Current is ____ Proportional to Resistance for a Constant Voltage
INVERSELY
83
The unit of electrical power is
WATT
84
____ is how much work is done over time
POWER
85
One watt of power is equal to the work done in one second by ____ moving one coulomb of charge.
ONE VOLT
86
Unit of resistance is named after
GEORG OHM
87
is a measure of how much a resistor resists the flow of electricity
RESISTANCE
88
(T/F) The magnitude of resistance is dictated by electric properties of the material and material geometry.
TRUE
89
conductors that exhibit the property of resisting current flow are called
RESISTORS
90
A resistor is a
DISSIPATIVE ELEMENT
91
RESISTOR converts electrical energy into ____.
HEAT ENERGY
92
G = 1/R is termed as the conductance of conductor. It's unit is
mho (℧)
93
sensor that detects light condition
PHOTORESISTOR
94
sensor that detects temperature condition
THERMISTOR
95
sensor that detects load condition
STRAIN GAUGE
96
Resistor is used in lowering voltage levels
VOLTAGE DIVIDER
97
In electronic circuits, resistors are used as pull-up and pull-down elements to avoid ____.
FLOATING SIGNAL LEVELS
98
decomposition of carbon film on a ceramic core
CARBON FILM
99
carbon powder and glue-like binder
CARBON COMPOSITION
100
ceramic core coated with metal oxide
METAL OXIDE
101
There are usually ___ bands of color on a resistor.
4 TO 6
102
is the limit on how far the real value of the resistor can deviate from its color coded value
TOLERANCE
103
a normal resistor with an additional arm contact that can move along the resistive material and tap off the desired resistance
VARIABLE RESISTOR
104
For a resistor with homogeneous material,
R = ρL/A
where ρ is ___
specific resistance of material
105
Find the current I through a resistor of resistance R = 2 Ω if the voltage across the resistor is 6 V.
I = 3A
106
is the rate of doing electrical work
ELECTRIC POWER
107
1 WATT = 1 Volt.Ampere or
1 Joule/sec
108
Formula for power
P = V·I
109
Formula for Electric energy
```
E = P·t
E = V·I·t
```
110
An ____ measures current
AMMETER
111
A ____ measures voltage
VOLTMETER
112
An ____ measures resistance
OHMMETER
113
A ___ combines these functions, and possibly some additional ones as well, into a single instrument
MULTIMETER
114
A voltmeter is connected in ___
PARALLEL CONNECTION
115
An ammeter is connected in ___
SERIES
116
An ohmmeter is connected in ___
WITHOUT ANY POWER SUPPLIED
117
The cell stores ___ and transfers it to electrical energy when a circuit is connected.
CHEMICAL ENERGY
118
When two or more cells are connected together we call this a ___
BATTERY
119
An electric current is a flow of microscopic particles called __ flowing through wires and components.
ELECTRONS
120
The current flow from the ___ terminal to the ___ terminal of a cell.
NEGATIVE, POSITIVE
121
The components are connected end-to-end, one after the other.
SERIES
122
The components are connected side by side. The current has a choice of routes.
PARALLEL CIRCUITS
123
Formula for resistors in series
Rtotal=R1+R2
124
Formula for resistors in parallel
1/Rt = 1/R1 + 1/R2 + 1/R3 + ...
125
In a circuit, resistors R1 and R2 are in series and have resistances of 5 Ω and 10 Ω, respectively. The voltage across resistor R1 is equal to 4 V. Find the current passing through resistor R2 and the voltage across the same resistor.
```
I2 = 0.8A
V2 = 8V
```
126
In a circuit, resistors R1 and R2 are in parallel and have resistances of 8 Ω and 4 Ω, respectively. The current passing through R1 is 0.2 A. Find the voltage across resistor R2 and the current passing through the same resistor.
```
V2 = 1.6V
I2 = 0.4A
```
127
The current passing through a resistor in a circuit is 0.01 A when the voltage across the same resistor is 5 V. What current passes through this resistor when the voltage across it is 7.5 V?
I = 0.015A
128
An ammeter must have a ___ input impedance
VERY LOW
129
(T/F) For series circuit, the current is the same at all points in the circuit.
TRUE
130
(T/F) For series circuit, the current is shared between the components
FALSE
131
The ‘electrical push’ which the cell gives to the current is called
VOLTAGE
132
A voltmeter should have a ___ input impedance
VERY HIGH
133
Scientist usually use the term ___ when they talk about voltage.
POTENTIAL DIFFERENCE
134
(T/F) In series circuit, the voltage is shared between the components
TRUE
135
(T/F) In parallel circuit, the voltage is the same in all parts of the circuit
TRUE
136
An electric iron of resistance 20 ohm draws a current of 5 amperes
500W
137
A resistance of 40 ohms and one of 60 ohms are arranged in series across 220 volt supply.
484W
138
A resistance of 25 ohm is connected to a 12 V battery
5.76W
139
The algebraic sum of voltage around a loop is zero
KIRCHOFF'S VOLTAGE LAW
140
Algebraic sum of all currents entering and leaving a node is zero.
KIRCHOFF'S CURRENT LAW
141
Voltage drop across each passive element is in the direction of current flow.
KIRCHOFF'S VOLTAGE LAW
142
Current entering a node is assigned positive sign. Current leaving a node is assigned a negative sign.
KIRCHOFF'S CURRENT LAW
143
The sum of the currents entering a junction is equal to the sum of the currents leaving that junction.
Kirchoff’s first law
144
The sum of the emf’s around any closed loop must equal the sum of the IR drops around that same loop.
Kirchoff’s second law
145
When applying the voltage rule, emf’s are___ if normal output direction of the emf is with the assumed tracing direction.
POSITIVE
146
When applying the voltage rule, I drops are ___ if the assumed current direction is against the assumed tracing direction.
NEGATIVE
147
uses a microammeter whose pointer
moves over a scale calibrated for all the different
measurements that can be made
ANALOG MULTIMETER
148
display the measured value in
numerals, and may also display a bar of a length
proportional to the quantity being measured
DIGITAL MULTIMETER
149
```
This
is where
all the measuring
scales of different
functional ranges are
displayed
```
SCALE PLATE
150
```
It
will snap
and indicate the
value or status you
measured
```
POINTER INDICATOR
151
A
rotary switch
to select appropriate
range
RANGE SELECTOR SWITCH KNOB
152
ranges use
when performing
resistance test
OHM RANGES (MULTIPLIERS)
153
ranges use
when performing
direct current voltage
test
DCV RANGES
154
ranges use
when performing
alternating current
voltage test
ACV RANGES
155
```
It
is use for
calibration of the
pointer before
resistance test
```
ZERO OHM ADJUSTER KNOB
156
```
It
is use for
calibration of the
pointer if needed
specially before
voltage test
```
ZERO VOLT CORRECTOR
157
```
It
is a physical
device use to
connect electronic
test equipment to
device under test
```
TEST PROBE
