How long does it take to change a light bulb? According to iSuppli, a market-research company that specialises in technology trends, the answer is 131 years. That is the amount of time that will have elapsed between 1879, when Thomas Edison first demonstrated his incandescent light bulb, and 2010, when semiconductor-based light-emitting diodes (LEDS) are expected to have made significant inroads into general illumination, a market worth $15 billion.
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