Total Final

Electricity

The flow of electrons.

Conductor

A material that allows electricity to flow easily (usually 1–3 valence electrons, e.g.,

Insulator

A material that resists electrical flow (5–8 valence electrons, e.g., glass, wood, air).

Semi Conductor

A material that are not good as a conductor or insulator, made up of atoms with the valance ring with 4 electrons

–Carbon (C)

–Silicon (Si)

Positive Ion

When an atom looses an electron

Negative Ion

When an atom gains an electron

Voltage

Electrical pressure (pushes current)

Volt

Unit of measure in Voltage

Ways to create voltage

Magnets

Chemical

Pressure

Heat

Light

Friction

Current

The directed movement of electrons or the flow. (pushed by voltage)

Amp

Unit of measure for current

One coulomb

6.25 X 10 to the 18^th power of electrons past a given point per second

Conventional theory

Says that current flows from + to -

Electron theory

Says that current flows from – to +

Resistance

Opposition to current flow (anything that slows down current)

Ohm

Unit of measure of resistance

Factors that affect the resistance of a circuit

Type of material used

•Conductor / Insulator / Semi-conductor

Length of the circuit

Diameter of the circuit

Temperature

Connections

AWG

American wire gauge

Ohm’s Law

When the voltage and resistance are equal in a circuit, ONE  amp will flow

To get more current

–Increase voltage

–Decrease resistance

–Or both

To get less current to flow

–Decrease voltage

–Increase resistance

–Or both

Ohm’s law formulas

E=I*R

Series Circuit Rules

Only one path

Amperage stays the same

Each resistance adds up to the total

–R1+R2=Rt

Voltage divided between the loads (all used up or dropped)

Voltmeters

Hooked across or in parallel

-Red to most positive and black to most negative

-Used in a live circuit

Ammeters

Hooked in series (in line and part of the circuit)

•Red to most positive and black to most negative

•Used in a live circuit

Ohm Meters

Used in a dead circuit

Must be hooked across or in parallel

Analog meter must be calibrated to compensate for battery

Part you want to measure must be isolated from the rest of the circuit

Good connections

Parallel Circuits

The total resistance of a parallel circuit is going to be smaller then the individual resistances 1/ ((1/R1)+(1/R2)+(1/R3))

Open Circuit

No flow

Infinite resistance

Won’t use circuit protection

Meters to find open

•Volt (will read source voltage across open)

•Ohm (will read infinite across open)

High resistance

Less flow than normal

Won’t use circuit protection

Meters to find

•Voltmeter (will drop more voltage at problem)

•Ohmmeter (will read more resistance at problem)

Short circuit

More flow than normal

May  use circuit protection

Meters to use

•Ohmmeter (less resistance at problem)

•Voltmeter (only if circuit is still live, voltmeter will read less voltage drop at problem)

Grounded circuit

Huge flow (no resistance)

Will use circuit protection or burn up circuit

Ohmmeter is the only meter to use (circuit will be dead)

•Ohmmeter will show no resistance to ground at the problem

Short to voltage

Hardest to find and fix

When one circuit shorts voltage into another

Low voltage

Won’t use circuit protection

Less amps will flow

Caused by

•Bad battery

Charging system fault

DIRECT CURRENT  

–flows in a single direction. The direction of flows depend on the polarity of the applied voltage. Most automotive vehicles’ electrical circuits us DC current.

ALTERNATING CURRENT

–changes its direction of flow in a regular and predictable way, current moves back and forth in the circuit, reversing direction whenever the polarity of the applied voltage changes.

Class A

a type of fire classification indicating flammable materials like wood, paper, and cloth.

Class B

a type of fire classification for flammable liquids and gases such as gasoline, oil, and paints.

Class C

a type of fire classification for electrical fires involving current-carrying equipment, such as wiring, appliances, and motors.

Class D

a type of fire classification for combustible metals like magnesium, titanium, and sodium.

box wrench

bristol

cap nut

carriage bolt

castellated nut

clevis pin

clutch

combo wrench

Corrosion

• skin burn

• eye damage

• corrosive to metals

diagonal cutting pliers

dowel pin

e ring

Environment

• aquatic toxicity

external tooth washer

fillister head screw

Flame over Circle

• oxidizers

Flammable

• flammable

• pyrophoric

• self-heating

• emits flame

flathead screw

g2

g5

g8

Gas cylinder

• compressed gas

Health Hazard

• carcinogen

• mutagenicity

• reproductive, organ, aspiration toxicity

hex head

internal tooth washer

jam nut

keeper nut

lag screw

long chain nose pliers

nut driver

open end wrench

oval head screw

pan head screw

pin extractor

pin punch

prong tee nut

ratchet drive wrench

roll pin

round head screw

screw starter

self tapping machine screw

sheet metal screw

slip joint pliers

slotted

split lock washer

spring hook tool

square key

stainless steel

standard nut

stop nut

tapered pin

thumb screw

tinnerman nut

tongue and groove pliers

tru arc inside

tru arc outside

tru arch pliers

truss head screw

woodruff key

Exclamation mark

• Irritant

• Skin Sensitizer

• Acute Toxicity

• Narcotic Effect

• Respiratory Tract Irritant

• Hazard to Ozone

Exploding Bomb

• Explosives

• Self Reactive

• Organic Peroxides