1 INTRODUCTION TO ELECTRICAL THEORY

2 What is Electricity? The controlled flow of electrons in an electrical circuit. A circuit must always be a complete loop.

3 Building Blocks Atoms Nucleus Protons (+) Neutrons Electrons (-)

4 Watch polarity Dont cross wires + - Polarity plugs

5 ATOMS

6 Conductors Let electricity flow readily Few electrons in outer shell 1 or 2 electrons Free electrons in outer shell Copper, gold, silver Platinum, aluminum, water 2S 8p

7 Insulators Do not let electrons flow Outer shell full or close to full electrons Full outer electron shell Glass, plastic Porcelain, wood Rubber

8 Circuit Essentials Source – Battery and Alternator Path – Wires or Chassis Wire size determine amp flow Wire measure in gauge (AWG) Bigger gauge = smaller wire Load – The device the electricity runs: motors, lamps, sensors, relays or electronic devices.

9 Other Circuit Components Switches Circuit Protection Fuse Circuit breaker Voltage limiter Fusible link Resistors Fixed Variable Relays Allows small current to control a large current ie Computer controls motor Solenoids Capacitors Integrated Circuits Wiring Printed Circuit Boards Wiring Diagrams

10 TYPES of CIRCUITS Simple Chassis ground One wire Series Parallel Series/parallel

11 SIMPLE CIRCUIT/1 wire

12 SERIES CIRCUIT

13 PARALLEL CIRCUIT

14 SERIES / PARALELL

15 Electrical terms Circuits Open Closed Continuity Shorts Open (wire broken) Short circuit (2 hot wires touch) Short to ground (wire to chassis) current increases

16 Shorts Open (wire broken) Short circuit (2 hot wires touch) Short to ground (wire to chassis) current increases

17 Three Measures of Electricity Voltage or Volts. This the push on the electrons by the source. In fancy terms known as electromotive force. Amperes or Amps. This measure is literally the amount of electrons. A coulomb is 6 billion billion electrons. Resistance. The resistance or opposition to the flow of electrons usually in the load device. Measured in Ohms.

18 OHMs Law E = Voltage I = Current R = Resistance It requires one VOLT to push one AMP through one OHM of resistance.

19 E = VOLTAGE E = I x R 2 amps x 5 ohms = 10 volts

20 VOLTAGE The push of the electricity Labeled E or V Magnetic Chemical Measured in Volts

21 CURRENT The Amount of Electricity

22 Current Direct current Cars Batteries AC - households Alternating current

23 I = Current I = E / R

24 Resistance Opposition to the flow of Electrons Measured in OHMs

25 R = Resistance R = E / I IF R = 0 THERE IS RESISTANCE… Just very very low

26 Resistance is affected by... Diameter of the wire Temperature of the wire Length of the wire Material wire if made from

27 Resistance Total Series circuit Rt = R1+ R2 + R Parallel 2 resistors (R1xR2) / (R1+R2) Parallel with More than 2 resistors (1) (1/R1) + (1/R2) + (1/R3) + (1/r4) + (1/Rx)

28 Electron Theory Electricity moves from - to + Electricians Scientists

29 Conventional Theory Electricity moves from + to – Automotive

30 MEASUREMENT TOOLS Voltage Meter Multi-Meter Test Light DVOM AMMETER Scan Tools Scope Jumper wires

31 Meter Hook-Ups

32 Electromagnetism Fundamentals of Magnetism Like charges repel Dissimilar charges ATTRACT Magnetic fields surround a wire flux Magnetic Circuits and Resistance Starters Solenoids alternators Induced Voltage Magnets can form voltage Voltage can form magnets Wire passes a magnet forces electrons to move in the wire------; current

33 Meter hook up Measure voltage in parallel hook up Measure amperage in series Measure resistance with the circuit off

34 PREFIXES Milli =.001 BASE Kilo = 1000 Mega = Thus 1 mV =.001V = KV = MV OR 1MV = 1000KV = V = mV