# MOTOR VEHICLE ELECTRICS INTRODUCING OHMS LAW BY PAUL MOTOR VEHICLE ELECTRICS INTRODUCING OHMS LAW BY PAUL LANE Original Power Point Created by Paul Lane Modified by Georgia Agricultural Education Curriculum Office June 2002 WHERE DID OHMS LAW COME FROM? Ohm, Georg Simon BORN: March 16, 1789, DI ED: J uly 6, 1854, Munich

Erlangen, Bavaria [Germany] German physicist who discovered the law, named after him, which states that the current flow through a conductor is directly proportional to the potential difference (voltage) and inversely proportional to the resistance. Ohm became professor of mathematics at the J esuits' College at Cologne in 1817. While his work greatly influenced the theory and applications of current electricity, it was so coldly received that Ohm resigned his post at Cologne. He accepted a position at the Polytechnic School of Nrnberg in 1833. Finally his work began to be recognized; in 1841 he was awarded the Copley Medal of the

Royal Society of London and was made a foreign member a year later. The physical unit measuring electrical resistance was given his name: OHMS LAW. OHMS LAW TO UNDERSTAND OHMS 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 OHMS LAW WHAT IS OHMS 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 OHMS. CALCULATE HOW MUCH CURRENT IS FLOWING THROUGH THE HEATED WINDOW. V = 12 VOLTS V

I R = 18 OHMS USING THIS SIMPLE TRIANGLE WE CAN SEE THAT: R I=V R I = 12 18 I = 0.6