OHM’S LAW INTRODUCING MOTOR VEHICLE ELECTRIC’S BY PAUL LANE Original Power Point Created by Paul Lane Modified by Georgia Agricultural Education Curriculum Office June 2002

WHERE DID OHM’S LAW COME FROM?

OHM’S LAW TO UNDERSTAND OHM’S LAW WE MUST FIRST LEARN SOME SIMPLE ELECTRICAL SYMBOLS: SINGLE CELL FUSE SINGLE ACTION SWITCH CAPACITOR BULB RESISTOR

ELECTRICAL SYMBOLS ONE WAY DIODE VARIABLE RESISTOR EARTH WIRES CROSSING WIRES JOINING IGNITION COIL CONTACT POINT

OHM’S LAW WHAT IS OHM’S LAW? V= I  R Where: V = VOLTAGE I = CURRENT R = RESISTANCE EXAMPLE: A 12 VOLT BATTERY SUPPLIES POWER TO A HEATED REAR WINDOW WHICH HAS A RESISTANCE OF 18 OHM’S. CALCULATE HOW MUCH CURRENT IS FLOWING THROUGH THE HEATED WINDOW.

V I R USING THIS SIMPLE TRIANGLE WE CAN SEE THAT: I = V R 12 I = 18 V = 12 VOLTS R = 18 OHM’S USING THIS SIMPLE TRIANGLE WE CAN SEE THAT: V I = V I R R 12 I = 18 I = 0.6 