Mod 1 Flashcards
The center part of the atom is the…?
nucleus
The nucleus contains the ___ and the ____.
proton and the neutron
Orbiting the nucleus in energy levels, or shells, is the…?
electron
The proton has a ____ electrical charge
positive
The neutron is ____ (has no charge).
neutral
The electron is a small particle orbiting in energy levels around the nucleus and has a _____ electrical charge.
negative
Since opposite charges (+ and –) cancel each other, the atom is electrically ____ or balanced.
neutral
If atoms are not neutral, they are ____.
ions
A positive ion, shown in Figure 1- 2B, has two protons in the nucleus, but only one electron in orbit. The one (1) negative charge does NOT cancel the two (2) positive charges, so the atom is not neutral. Since it has one more proton than electron, the atom has a ____ charge and is a ____ ion.
positive charge and is a positive ion
A negative ion, shown in Figure 1-2C, contains two protons and three electrons. It has a ____ charge.
negative
For an atom to become an ion, it must lose or gain electrons in its…?
outer shell
____ is the gain or loss of an electron.
Ionization
The inner shell has the ___ attraction to the nucleus and has the least amount of energy.
most
The outer shell has the least attraction to the nucleus and the ___ amount of energy.
most
___ ___ are the electrons in the outermost shell of an atom.
Valence electrons
If a valence electron absorbs sufficient energy, it attempts to move to a higher shell, further from the nucleus. In the process of moving, it can escape the attraction of the nucleus, and becomes a ___ ___.
free electron
The ____ of atom determines amount of energy needed to free an electron.
type
Depending on their ability to conduct electricity, all elements of which matter is made may be placed into one of three categories:
conductors, semiconductors, and insulators.
Conductors are elements which conduct electricity very…?
readily
Insulators ____ the conduction of electricity.
oppose
All matter between conductors and insulators may be called…?
semiconductors
Conductors have many ___ ___ that move easily from atom to atom.
free electrons
The electrical conductivity of matter depends on the ___ ___ of the material from which it is made.
atomic structure
___ ___ is one method of removing electrons from their orbits.
Heat energy
When controlled by an electrical force, the electrons move generally in the same direction. The effect of this movement is felt almost instantly from one end of the conductor to the other. The electron movement is called ____ ____.
electric current
Some metals are better conductors than others. ____, ____, ____, and ____ have many free electrons which make them good conductors. Additionally, these materials have relatively low resistance which allows the electrons to move easily.
Silver, copper, gold and aluminum
Each type of conductive material has a different amount of
____ ____. Resistance will be explained in greater detail later in the studies, but for now consider that the higher the value of resistance, the greater the opposition to the movement of electrons.
relative resistance
Nonconductor materials have very few free electrons. These materials are called ____.
insulators
Some examples of insulators are:
Rubber, plastic, enamel, glass, dry wood, and mica.
Some materials are neither good conductors nor good insulators. Their electrical characteristics fall between those of conductors and insulators. These materials are classified as ____.
semiconductors
Germanium and silicon are two common _____ used in electronics.
semiconductors
______ is the force, or electrical energy, required to move electrons from one place to another.
voltage
Chemical action within a battery produces this energy.
voltage
The ___ ___ causes an excess of electrons on the negative terminal and a shortage of electrons on the positive terminal. The forces created by this different charge between the terminals produce the force necessary to move electrons through a conductor.
chemical action
Symbol for Voltage
E
Unit of Measurement for Voltage
Volt
Voltage Symbol for Unit of Measurement
V
In your career as an electronics technician, you may notice that __ and __ are interchangeable symbols for voltage.
V and E
Total voltage of a circuit uses the subscript (), for applied, and will be written as E.
a
The energy or force used to move electrons has several names. All these names mean essentially the same thing and you should be familiar with them. Those names are?
electromotive force (EMF), potential, difference of potential, or voltage
____ is the movement of free electrons through a conductor.
Current
The rate of movement for current is measured in _____.
amperes
The ____ is a measure of the amount of electric charge passing a point per unit time.
ampere
The ampere is a ___ ___. It represents the flow of 6,280,000,000,000,000,000 electrons past a point in a conductor each second.
base unit
The unit of charge, known as the _____, is the quantity of electricity carried in 1 second by a current of 1 ampere.
coulomb
Symbol for Current
I
Current’s Unit of Measurement
Ampere
Current’s Symbol for the Unit of Measurement
A
Total current of a circuit uses the subscript () for total and will be written as I.
t
_______ is the opposition a device or material offers to the movement of electrons.
Resistance
Symbol for Resistance
R
Resistance Unit of Measurement
Ohm
Resistance Symbol for the Unit of Measurement
Ω (Greek Letter Omega)
Total resistance also uses the subscript () and is written as R.
t
Conductance is an expression of the ease with which electric current flows through materials like ___ and ___.
metals and nonmetals
______ is the degree to which an object conducts electricity, calculated as the ratio of the current which flows to the potential difference present.
Conductance
This is the reciprocal of the resistance and is measured in siemens or mhos.
Conductance
Symbol for Conductance
G
Conductance Unit of Measurement
siemens or mhos
Conductance Symbol for Unit of Measurement
℧
In electromagnetism and electronics, ____ is the tendency of an electrical conductor to oppose a change in the electric current flowing through it.
Inductance
The flow of electric current through a conductor creates a magnetic field around the conductor, whose strength depends on the magnitude of the current. A change in current causes a change in the ___ ___.
magnetic field
Symbol for Inductance
L
Inductance Unit of Measurement
Henry
Inductance Symbol for Unit of Measurement
H or h
Inductance is defined as the physical property of a circuit that ____ changes to current flow.
opposes
It is also the ability of an inductor to store energy in the form of an electromagnetic field.
Inductance
An electronic component designed to add inductance to a circuit is called an _____.
inductor
It typically consists of a ____ or helix of wire.
coil
The unit of measurement for inductance is the ____.
Henry
____ is the ability of a dielectric to store an electric charge. It may loosely be defined as the property of a circuit that enables it to store electric energy by means of an electrostatic field and to release this energy later.
Capacitance
It is also the ability of a capacitor to store energy in an electrostatic
field in the form of ____.
voltage
It typically consists of two conductive plates separated by an insulating material known as a _____.
dielectric
The unit of measurement for capacitance is the ____.
Farad (F)
Symbol for Capacitance
C
Capacitance Unit of Measurement
Farad
Capacitance Symbol for the Unit of Measurement
F
____ is the rate of doing work.
Power
Work results from force acting on mass over a ____.
distance
The operation of electrical circuits involves force (____) acting on mass (____) over a distance.
voltage
electrons
Energy is the ___ ___ ___ ___, so in electrical circuits, energy is transformed into heat energy.
capacity to do work
Power is the measure of how much energy is being converted to ____.
heat
Symbol for Power
P
Power’s Unit of Measurement
Watt
Power’s Symbol for the Unit of Measurement
W
___ ___ states that the amount of current in a circuit is directly proportional to the amount of applied voltage and inversely proportional to the amount of circuit resistance.
Ohm’s Law
Ohm’s Law is applied to ____ configurations to calculate voltage, current, and resistance.
circuit
Ohm’s Law is normally expressed in the formula: _____ (Current is equal to voltage divided by resistance).
I = E/R
Current equals voltage divided by resistance. You can solve for current (I) if you know voltage (V) and resistance (R). The formula for current is…?
I = V/R
Resistance equals voltage divided by current. You can solve for resistance (R) if you know voltage (V) and current (I). The formula for resistance is…?
R = V/I
Voltage equals current times resistance. You can solve for voltage (V) if you know current (I) and resistance (R). The formula for voltage is…?
V = IR
There are two basic types of circuits:
series and parallel
The minimum requirements for a circuit are:
- Power supply (battery, difference of potential, voltage)
- Load device (resistance, lamp)
- Conductor (wire, continuity)
A ___ ___ is an electrical component, such as a light bulb or a stereo system, connected to and drawing current from a voltage source.
load device
Every load device has a certain amount of opposition to that circuit. ____ ____ is the resistance or opposition of the load device to current.
load resistance
___ ___ is the current drawn from the voltage source by the load device.
load current
To make a circuit more practical additional devices must be added to control, protect, and monitor the circuit:
- Protective device (fuse/circuit breaker)
- Control device (switch)
- Monitoring device, (meter) (ammeter, ohmmeter, voltmeter)
According to the ___ ___ ___ ___, like charges repel each other while unlike charges attract each other.
Law of Electrical Charges
The ____ circuit is the simplest circuit
series
All circuits, no matter how complex, can be broken into any number of simple ____ circuits.
series
If the series circuit has one resistor, total resistance is equal to the value of that resistor. If the series circuit has more than one resistor, the values of all the resistors must be ____ together before you calculate current.
added
In a series circuit, current flows in…?
one path
Remember, current is the ____ at every point in a series circuit.
same