Forty percent of that powers old-fashioned incandescentlight bulbs—a 19th-century technology that wastes most of the power it consumes on unwanted heat.
The incandescentlight bulb, invented by Thomas Edison, which came to be the symbol of inspiration, has been developed into hundreds, if not thousands, of forms.
托马斯·爱迪生发明的白炽灯成为了灵感的象征，现在已经演变成数百种甚至数千种形式了。
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Old-style incandescentlight bulbs generate heat as well as light.