Download Ch 2 PPt 1 Basic Theories

ATM 202 Automotive
Electricity
Instructor : Matthew Pence
Email: [email protected]
Book:Automotive Electricity &
Electronics 2nd Ed. Barry Hollembeak
Hours: Monday 6:00pm – 9:30pm
Wednsday 6:00pm – 10:00pm
• The Atomic Structure
•What is an Atom?
• An atom is the smallest particle
on any element.
• Element – oxygen (O) or
hydrogen (H)
• Compound – two or more
elements combined together –
water (H2O)
• Molecule – Smallest particle of a
compound
• Atom Basics
• Valence Ring
• Free Electrons
Conductor
• Supports the flow of electrons
• Popular Conductors:
– Copper, Silver, gold, iron, aluminum
– Each have three or less free
electrons in it’s valence ring.
Insulators
• Cannot support the flow of
electrons
• Five of more free electrons in
it’s valence ring
• Popular insulators:
– Glass, plastic, rubber, paper, wood
Semiconductors
• Not good conductors or
insulators
• Four free electrons in valence
ring.
• Silicon most popular, made from
sand
Electricity
• Electricity is the flow of
electrons through a conductor.
• The human body runs on
electrical impulses
• The human body conducts
electricity!!!
Electrical Theories
• Electron theory – electrons
moving from negative to positive
• Conventional theory – electrons
flow from positive to negative
• Does it make a difference?
Electromotive Force Voltage
Electrical Flow – Current
AC/DC – Highway to Hell
• Alternating current – Voltage
that moves from positive to
negative at a frequency that can
vary
• Direct Current – Voltage stays
the same in moves in one
direction
Electrical Restriction –
Resistance
Review
• Voltage – Electrical pressure,
potential, measured in Volts
• Current – Flow of electrons past a
certain point in a given time,
measured in Amps: 6.25 Billion
Billion electrons per second = 1 amp
• Resistance – Opposition to current
flow, load or work, consumes
voltage, measured in ohms