Page 46 - Electromechanical Devices and Components Illustrated Sourcebook

8 Electromechanical Devices & Components Illustrated Sourcebook

Watts it will produce 100 watts of work. In the case of a light bulb,
the work is in the form of light emissions.
Watt is an important unit of measure to have knowledge of
120 volts 0.83 amps 100 watts
when discussing basic electricity. It is one of the most com-
mon terms used in electricity. We have all considered what It is also important to understand that if you know the
wattage the light bulb should be when replacing a burned out wattage of a device and either the voltage or current, then you
one. Most of us have heard of stereo equipment rated in watts. can use Ohm’s law to determine the resistance.
Hair dryers and heaters are usually rated in watts. We all know To derive current from wattage divide the watts by the
that a 2000 watt heater produces more heat than a 1000 watt voltage.
unit. But what is a watt?
The watt is a unit of measure that describes work. When 100 watts 120 volts 0.83 amps
considering electrical circuits, the total watts are derived by
To find the resistance with Ohm’s law.
multiplying the voltage by the current. As an example, if a
light bulb operates on 120 volts and requires 0.83 amps then 120 volts (E) 0.83 amps (I) 144.6 ohms (R)