Transcript Ohm`s Law PowerPoint

INTRODUCING
OHM’S LAW
Original Power Point Created by Paul Lane
Modified by Georgia Agricultural Education Curriculum Office
June 2002
WHERE DID OHM’S LAW COME
FROM?
Georg Simon Ohm
BORN: March 16, 1789, Erlangen, Bavaria [Germany]
DIED: July 6, 1854, Munich
German physicist who discovered the law that 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 Jesuits' 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 Nürnberg 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.
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
WHAT IS OHM’S LAW?
V= I x 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 following through the
heated window.
Using this simple triangle we can see
that:
V
I
R
I=V
R
I=
V = 12 VOLTS
I=
12
18
0.6
R = 18 OHM’S
ANSWER:
About 6 amps of current followed through the heated
window.