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INTRODUCTION TO ELECTRICITY INS J.BAU Departament de Tecnologia
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Electrical Energy and Power If it weren't for electricity we'd all be watching television by candlelight. -George Gobal
What is Electricity? 3
Atoms are made up of three primary components Protons Neutrons Electrons
Figure 9 From: Cambridge Physics Outlet, MA URL: http://www.vtaide.com/png/atom.htm
When electrons move from atom to atom, we call that electricity
What are electricity’s characteristics? 4
Voltage
Current
The quantity of electrons that pass through a wire or other conductor in one second. You can also think about it like the width and depth of a river.
Resistance
The amount of “pressure” behind the electrons forcing them to move from atom to atom. You can also think about it like the steepness of a river.
How hard it is for the electrons to move through something. You can also think about it like the number of rocks and trees and other debris slowing down a river.
Power
The ability of the electricity to do a certain amount of work in a certain time (voltage x current). You can also think about this like the overall “power” or a river (how steep it is x how much water is running in it).
Important Equations 5
Ohm’s Law, Georg Ohm, 1827
V=I*R
Power Equation
P=V*I
Power 6
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Power is simply Energy/Time
P = E/t