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How can Electrical Power be Calculated?

To calculate the power of a component we need to
measure the voltage across the component
and the current flowing through the component.

We can show how to calculate power using a lamp
(an electric light). The circuit below
shows where to place an ammeter and a voltmeter.

Ammeter and a Voltmeter in a Circuit

Power = voltage x current     P = V x I

If the ammeter reads 2 A and the voltmeter reads 6 V

then  P = V x I
             = 6 x 2
                    = 12 watts.

The power of the lamp above is 12 watts.

The same method can be used
to calculate the power of any component.

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