Ohm’s Law page 2

We can use the energy of the spinning axle to do work (convert energy). The job in this example is to lift 33,000 pounds 1 ft. in 1 minute. One healthy draft horse can do it, so we’ll call this motor a 1-horsepower motor (1 hp = 33,000ft. lb./min.). Power is the rate at which work is done. More power means more energy is being transferred from one form to another. The rate at which electricity is converted to another form of energy (heat, light, motion) is measured in Watts. The power formula is the most commonly used formula for electrical work. It is essential to understanding its application. That formula is expressed as follows:

P (power in watts) = I (amps) x E (volts)


This formula is also useful to utility companies. They can move large amounts of power through small low-current wires by distributing it at high voltage, then lowering the voltage with transformers near the point of use by the customer.

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