MOTOR VEHICLE ELECTRIC’S

INTRODUCING

OHM’S LAW BY PAUL LANE

Ohm, Georg Simon

BORN: March 16, 1789, Erlangen, Bavaria [Germany]DIED: J uly 6, 1854, Munich

German physicist who discovered the law, named after him,which states that the current flow through a conductor is directlyproportional to the potential difference (voltage) and inverselyproportional to the resistance.Ohm became professor of mathematics at the J esuits' College atCologne in 1817. While his work greatly influenced the theory andapplications of current electricity, it was so coldly received thatOhm resigned his post at Cologne. He accepted a position at thePolytechnic School of Nürnberg in 1833. Finally his work began tobe recognized; in 1841 he was awarded the Copley Medal of theRoyal Society of London and was made a foreign member a yearlater. The physical unit measuring electrical resistance was givenhis name: OHMS LAW.

WHERE DID OHM’S LAW COME FROM?

OHM’S LAWTO UNDERSTAND OHM’S LAW WE MUSTFIRST LEARN SOME SIMPLE ELECTRICALSYMBOLS:

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 = CURRENTR = RESISTANCE

EXAMPLE:A 12 VOLT BATTERY SUPPLIES POWERTO A HEATED REAR WINDOW WHICHHAS A RESISTANCE OF 18 OHM’S.

CALCULATE HOW MUCH CURRENT IS FLOWING THROUGH THE HEATED WINDOW.

V = 12 VOLTSR = 18 OHM’S

V

I R

USING THIS SIMPLE TRIANGLEWE CAN SEE THAT:

I = VR

I = 1218

I = 0.6