1
The Power Equation
Electric power is the rate at which energy is converted from electrical engery to some other form
such as heat or mechanical energy. When charge moves through a reisistor it loses potential energy.
That energy is converted to heat. Power
dissipated
(as heat) by a component in a DC circuit is given
by the product of the voltage across the component and the current through the component:
For example, in the circuit below, how much power is dissipated in the 1.5 ohm resistor?
Solving for current first:
I = V/R = 1.5/1.5 = 1
therefore,
P = 1.5 * 1 = 1.5 Watts
alternatively,
P = I
2
* R, so
P = 1 * 1* 1.5 = 1.5 Watts
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 Winter '09
 TRAYLOR
 Energy, Volt, Resistor, electrical energy, 1.5 watts

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