week 1

GFCI protectors open the circuit when ____ of ground-fault current are sensed.

5 milliamperes

Nucleus

Center of an atom

Magnetic domains

Clustered regions of aligned magnetic atoms. When these regions themselves are aligned with one another, the substance containing them is a magnet.

Magnetic domains are

Clusters of atoms whose spins are aligned

English system of measurement

Flux density is measured in lines per square inch

Molecules

Groups of two or more atoms held together by chemical bonds

SI system

International System of units based on the metric system and units derived from the metric system

Procedures generally employed to prevent someone from energizing a piece of equipment by mistake

Lockout and Tagout

magnetic attraction

Magnetic force exerted by oppositely charged particles, tending to draw or hold the particles together.

What does MSDS stand for?

Material Safety Data Sheet

What is a MSDS sheet?

Material Safety Data Sheet

What does OSHA stand for?

Occupational Safety and Health Administration

_______ are caused by two conductors becoming shorted together

Parallel Arc Faults

As the Greek letter used to measure flux

Phi

What is the leading causes of electrical fires?

Poor connections

Reluctance is

Resistance to magnetism

reluctance

Resistance to magnetism

Why should a person work with only when hand when possible?

So that the current will not pass through the heart.

What is the most important rule of electrical safety?

Take time to think before acting. Always think.

Magnetic North

The direction a compass needle points (in the northern hemisphere)

True North

The direction to the geographic North Pole

valence electrons

The electrons in the outermost shell (main energy level) of an atom; these are the electrons involved in forming bonds.

Electron Spin Patterns

The idea that an electron spins on its axis making it a tiny permanent magnet.

Ampere-turns

The number of turns of wire multiplied by the current flow in an electromagnet.

Fibliration

a condition in which the heart begins to "quiver" and the pumping action stops.

Diamagnetic materials

are either metal or nonmetal materials that cannot be magnetized, magnetic lines of force tend to go around them instead of through them

The smallest part of an element

atom

Unlike poles

attract each other

opposite charges

attract each other

the spinning motion causes each electron to...

become a tiny permanent magnet

Alternating current is

bidirectional, which means that it reverses its direction of flow at regular intervals

that current flow is produced when an electron from one atom knocks electrons of another atom out of orbit.

bump theory

basic methods for producing electricity are 2

chemical action

Three substances that form natural magnets 3

cobalt

Clas d fire

consist of burning metal.

diamagnetic

copper, brass, and antimony

Examples of diamagnetic materials

copper, brass, and antimony.

electromagnet

dependent on electric current flow to produce a magnetic field

Electromagnets are

designed to produce a magnetic field only as long as the current is flowing

Flux density

determined by field strength and the arc in which the lines of flux are located

unidirectional

direct current

magnetic polarity

direction of magnetic north pull on earth

Electromagnets depend on

electric current flow to produce a magnetic field

Magnetic devices

electromagnets, measuring instruments, inductors, transformers, and motors.

horseshoe magnet

a magnet in the shape of a horseshoe, which has its north and south poles at each opposite tip

When a current flows through the coil of a electromagnet

a magnetic field is produced

ferromagnetic material

a material that shows strong magnetic properties; iron, nickel, cobalt, manganese

Photons can be produced when

electrons move from one energy level to another.

lodestone/magnetite

a mineral discovered by the Greeks that attracts materials containing iron

A speaker uses

a perminent and a electromagnet

Lockout and ragout procedures are used to prevent

a person from energizing a circuit by mistake.

lodestone

a piece of magnetite or other naturally magnetized mineral, able to be used as a magnet.

Semiconductors are used in the construction of

all solid-state devices, such as diodes, transistors, and integrated circuits.

Saturation occurs when

all the molecules of the magnetic material are lined up.

bidirectional

alternating current

Residual magnetism

amount of magnetism left in an object after the magnetizing force has been removed

magnetic molecules

another term for magnetic domains

magnetic lines of force

flux

Semiconductors contain how many valence electrons

four valence electrons.

basic methods for producing electricity are 6

friction

basic methods for producing electricity are 4

heat

lines of flux

imaginary lines that indicate the direction and strength of the magnetic field

Clas c fire

involves involves energized electrical equipment.

Three substances that form natural magnets 1

iron

natural magnet

iron, nickel, and cobalt

examples of ferromagnetic materials

iron, nickel, cobalt

Photon

is a massless particle of pure energy.

Permeability

is a measure of a material's ability to become magnetized

basic methods for producing electricity are 3

light

The law of charges states that

like charges repel each other and unlike charges attract each other

The earth is a

magnet

Magnetite

magnetic

whenever an electric current flows through a conductor, a

magnetic field is formed around the conductor

english system

magnetic strength measured in flux density.

basic methods for producing electricity are 1.

magnetism

Methods of producing electricity

magnetism, chemical action, pressure, heat, friction, light

electrical effects

magnetism, chemical reaction, pressure, heat, light

perminate magnet

magnets that do not require any power or force to maintain their field.

semiconductor

materials containing four valence electrons

Insulators

materials containing seven or eight valence elections

Insulators are

materials that do not provide an easy path for the flow of electrons.

Conductors are

materials that provide an easy path for electron flow.

Ferromagnetic materials

metals that are easily magnetized.

Paramagnetic materials

metals that can be magnetized, but not as easily

smallest part of a compound

molecule

demagnetize

molecules disarranged

Demagnetizing

molecules must be disarranged as they are in a nonmagnetized material

Magnetism

most common method of producing electricity

Ampere-turns are determined by

multiplying the number of turns of wire by the current flow.

Like charges

repel each other

Like poles

repel each other

electromagnets don't

retain their magnetism when current flow stops

Insulators are made from materials that contain how many valence electrons.

seven or eight valence electrons.

3lectron Spin Patterns

spin on their axes as they orbit the nucleus of the atom

Ways to demagnetize a magnet

striking it, heating it, or placing the object in the field of a strong electromagnet connected to an AC line

The polarity of the field is determined by

the direction of current flow

When the current flow reverses though the coil

the electromagnet has a south polarity and is attracted to the permanent magnet.

two factors that determine the number of flux lines produced by a electromagnet

the number of turns of wire and the amount of current flow through the wire

The three principal parts of an atom

the proton, the electron, and the neutron.

Molecules

the smallest part of a compound

when the electromagnet has a north polarity it is repelled from the permanent magnet causing

the speaker cone to move outward and displace air

Winding the wire into a coil increases

the strength of the magnetic field.

Gluons

the substance that holds quarks together

Direct current is

the unidirectional flow of electric charge

Think before you...

touch something that could coast you your life.

What is a ground fault?

When a path to ground is made that was not planned.

What is fibrillation of the heart?

When the heartbeat flutters and stops functioning properly.

What section of the NEC covers grounding?

250.

What is the approximate current at which a ground-fault detector will open the circuit?

0.005 amps.

How many valence electrons do materials used for conductors have?

1 to 3

how many times smaller is an electron than a proton

1,000 times

How many times more does a proton weigh than an electron?

1,838 times

What distance should the bottom of the ladder be placed from the side of the building?

1/4 of the ladder's height.

A current of how many milliamperes causes death?

100 to 200

What range of electric current generally causes death?

A current of 100 to 200 milliamperes causes death.

Arc-Fault Circuit Interrupter (AFCI)

A device intended to provide protection from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the circuit when an arc fault is detected.

Ground Fault Circuit Interrupter (GFCI)

A device that interrupts and de-energizes an electrical circuit to protect a person from electrocution.

magnetic repulsion

A force that pushes objects with the same poles away from one another.

AFCI

Arc-Fault Circuit Interrupter. Intended to provide protection from the effects of arc faults by recognizing characteristics unique to arcing and functioning to de-energize the circuit when this type of fault is detected

_________ circuit interrupters employ a microprocessor to sense an _______ condition.

Arc-fault interrupters

letter __ is used to represent flux density

B

What is the operating principle of a defibrillator?

The remove the current and return the heart to a normal pumping action.

GFCI

They work by sensing the amount of current flow on both ungrounded and grounded conductors supplying power to a device.

electrons have a

negative charge

Three substances that form natural magnets 2

nickel

Neutrons have

no charge

An atom of iron contains 26 electrons.

of these 22 are paired and spin opposite directions, canceling each other's magnetic effect

Conductors are made from materials that contain how many valence electrons.

one to three valence electrons.

Valence electrons are located

outer orbit of an atom

PPE

personal protective equipment

Paramagnetic

platinum, titanium, and chromium

Examples of paramagnetic materials

platinum, titanium, and chromium.

Protons have a

positive charge

basic methods for producing electricity are 5

pressure

Saturation

when all molecules of the magnetic material are lined up.

Light is produced...

when electrons move to a lower orbit and produce a photon

Left hand rule

wrap the four fingers of your left hand around the coil so that the fingers point in the direction in which the electrons are flowing from the negative terminal of the dry cell to the positive