Basics Of Automotive Electrical & Electricity. Matter. Anything that has mass & takes up space:. Matter. Can exist in three states Solids Liquids Gases. Molecule. Smallest portion of matter that still retains all of the properties of the original Molecules are made up of atoms.
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Matter • Anything that has mass & takes up space:
Matter • Can exist in three states • Solids • Liquids • Gases
Molecule • Smallest portion of matter that still retains all of the properties of the original • Molecules are made up of atoms
The Atom A n Atom is the smallest form of an element. Combining Atoms forms molecules that make up all matter. The term Electricity comes from the Greek word elektron, meaning: Amber. Amber is a fossil resin that Ancients rubbed with wool to produce static electricity. This was their way of “shocking” someone since they had no nylon carpet in their tents! - + N
The Atom • The word atom comes from the Greek ἄτομος/átomos, α-τεμνω, which means uncuttable or something that cannot be divided further • They are a basic unit of matter • They consist of a dense central nucleus surrounded by a cloud of negatively charged electrons & electrically neutral neutrons
Atoms • 100 + different types • One molecule of water is made up of one atom of oxygen, two atoms of hydrogen H20
All Atoms are made up of • Electrons • Protons • Neutrons
PARTS OF ATOMS 1. PROTON - part of nucleus, is positively charged 2. NEUTRON - part of nucleus that is neutral (has a positive & negative charge) 3. ELECTRON - orbits the nucleus, is negatively charged
An atom with more protons then electrons- is called a positive charged atomproton & neutron in center; electrons orbit
Bound electrons • Are in the inner orbits • Since bound electrons are very close to the center nucleus they have a strong magnetic attraction, they are very difficult to remove from their orbit
Free electrons • Located in the outer orbit only, one, two or three electrons, they loosely bound & are easily knocked out of their orbit
The negatively charged electrons of an atom are bound to the positively charged nucleus by electromagnetic force
An atom containing an equal number of protons & electrons is electrically neutral • an atom has a positive or negative charge it is considered an ion
Atomic Structure Determines How An Atom Acts • Insulators will have 5 – 8 electrons in their outer orbit • Semi Conductors will have 4 electrons in their outer orbit • Conductors will have 1 - 3 electrons in their outer orbit 1 conducts much better than 3
Conductors • Have 1-3 electrons in their outer orbit • Magnetic force is trying to pull them in closer & centrifugal force is trying to move them further out & away from the positively charged center or nucleolus • Since they are out in the outer orbit & the magnetic pull is weaker they are easily knocked out of their orbit
Semi-Conductors • 4 electronsin outer orbit • Not a good conductor • Not a good insulator
Non conductors • Insulators, 5 or more electrons in outer orbit, glass, ceramics, plastics, rubber, fiber, porcelain, paper & wood are common Insulators.
These electrons are much more difficult to knock out of orbit, they have a stronger magnetic force to each other because they are closer together & to the positively charged protons in the nucleus or center of the atom
Different Elements Each element has it’s own individual characteristics & each has a different number of electrons, protons, and neutrons circling the nucleus. No atom has more than eight electrons in the outer shell or valance ring. This is how we get different characteristics that are helpful in generating, conducting, & insulating electrical currents Orbits
A Negative ion - is an atom that has gained one or more negatively charged electrons A Positive ion - is an atom that has lost one or more negatively charged electrons LAW FOR CHARGES (Just like magnets) LIKE CHARGES REPEL UNLIKE CHARGES ATTRACT Current flow begins when electrons in a circuit move
Conductors Conductors are materials with 1 to 3 electrons in the outer orbit These electrons are loosely bound or not very close to the opposite or positively charged nucleus & they have a week magnetic attraction This allows these electrons to be easily given up as free electrons & they jump to another atom causing current flow Gold, Silver, & Copper are examples of a good conductors because they have only one electron in their outer orbit
Insulators Insulators are materials with 5 to 8 electrons in their outer orbit Because they have more electrons in their outer orbit they are in closer proximity to each other Because electrons are all negatively charged they repel each other & the electrons from other atoms thus they block or will not allow electrons to jump or join them Plastic, rubber, & ceramics are examples of good insulators
Semiconductors Semiconductors are neither conductors nor insulators. Semiconductors are materials that contain exactly 4 electrons in the atom’s outer orbit & are, therefore, neither good conductors nor good insulators. Silicone & germanium are examples of semiconductors
Conductor - has 1 to 3 outer orbit electrons Insulator - has 5 to 8 outer orbit electrons Semiconductor - has 4 outer orbit electrons
EXAMPLES Gold - 1 outer orbit electron Silver - 1 Copper - 1 Iron - 2 Aluminum - 3 PLASTIC RUBBER Silicon - 4 Germanium - 4
ECTROMOTIVE FORCE EMF - is the electrical pressure or force that causes electrons to flow in a circuit. EMF is measured in volts VOLTAGE - The pressure necessary to cause electron movement.
6 WAYS TO PRODUCE VOLTAGE 1. FRICTION 2. CHEMICAL 3. HEAT 4. LIGHT 5. PRESSURE 6. MAGNETISM
Electrons (energy) in a potential or stored state, are static not moving electricity Electrons in a discharged state (flowing) become kinetic moving electricity Electron movement in a circuit is called current flow CURRENT FLOW- Is caused because of a voltage imbalance 2 differing voltage levels trying to get balanced 12 Volts on the positive side & 0 Volts on the negative side Current flow is measured in amperes or amps. 1 Amp = 6,250,000,000,000,000,000 that’s 6.25 Billion Billion electrons per second passing a given point ina conductor
THEORIES OF CURRENT FLOW: CONVENTIONAL – STATES THAT CURRENT FLOWS FROM POSITIVE TO NEGATIVE Used in automotive wiring diagrams ELECTRON – STATES THAT CURRENT FLOWS FROM NEGATIVE TO POSITIVE
RESISTANCE - is anything that limits the flow of electrons (current flow) in a circuit Resistance is measured in OHMS. The resistance of an object is determined by : 1. The type or composition of the material. 2. The length of the material 3. The diameter of the material 4. The temperature of the material. Resistances can vary from allowing large amounts of current flow to allowing no current flow.
All materials including conductors have a certain amount of resistance Zero resistance cannot be achieved at normal temperatures In most materials resistance is directly proportional to temperature . As temperatures go up resistance goes up As temperatures go down resistance goes down
Ohms Law 1 volt of electrical pressure is required to push 1 amp of current through 1 ohm of resistance
Volts, Amps, & Ohms • Amps - • Discovered & named after Frenchman: André Marie Ampere (1775-1836) • 1. Unit of measurement for current flow. • 2. A and amps are acceptable abbreviations for amperes. • The capital letter I is for intensity - used in mathematical calculations. • 4. Amperes is measured using an Ammeter not an ampmeter • . Volts - Discovered and named after the Italian Scientist: Alessandro Volta (1745-1827) 1. Unit of measurement for electrical pressure. 2. Electromotive Force, EMF, is another way of indicating voltage. 3. The capital letter V is the acceptable abbreviation for volts. 4. The symbol used in calculations is the letter E, for EMF. 5. Voltage is measured using a Voltmeter. • Ohms - • The German scientist Georg Simon Ohm (1787-1854) discovered the relationship between volts amps and resistance and produced Ohms Law. • 1. Unit of measurement for electrical resistance. • The symbol for ohms is Ω the last letter of the Greek alphabet. • The symbol used in calculations is the letter R, for resistance. • Ohms are measured using an Ohmmeter.
A complete automotive circuit contains all of the following: 1. PowerSource – usually the battery or alternator 2. Conductors - wires, cables, circuit boards, etc. 3. Circuit Protection – usually a fuse or fusible link 4. Load(s) - the electrical device(s) to be operated 5. Control Device - switch, relay, microprocessor
SOURCES OF ELECTRICAL ENERGY Power Source
MAGNETIC • Coils • Alternators
LIGHT • Photo Cells
HEAT • Thermocouples
PRESSURE • Piezoelectric crystals Knock sensors
VOLTAGE • Electrical pressure or potential • Electromotive force causes the movement of electrons • Electrical pressure is measured in volts • Automotive electrical systems are considered 12 volt even though they are actually operate at higher voltages
VOLTAGE • Potential • Pressure • Measured in Volts • V • Electromotive Force • EMF • E
AMPERAGE • The movement of electrons from one atom to another • Trying to create a balance
AMPERAGE • The rate of electron flow • Measure in amperes or amps • If voltage goes up, current flow increases • If voltage goes down, current flow decreases
AMPERAGE • Flow of electrons • Current flow • Measured in Amps Ampere(s) • Amp(s) • A • Intensity • I
What does it take? • To make electrons or current flow, you must have a complete or closed circuit including a return or ground side path back to the power source • If more pressure (Volts) are applied more work can be done • If more electrons (Amps) are moving more work can be done • If there is less resistance or opposition to current flow (Ohms) more work can be done
Three factors effecting electron flow • Voltage • The amount of potential or electrical pressure • Amperage • The rate or speed of electron or current flow • Resistance • The amount of opposition to electron or current flow
RESISTANCE • Opposition to Current Flow • Restriction • Measured in Ohms • Omega symbol • R