This made it possible for long distance transmission of power. Thanks Mr. Tesla for making it possible to invent and use all those electrical houshold devices we take for granted including phones, stoves, furnace, TV, computers, etc.
Philips' LED bulb emits the same amount of light as its incandescent equivalent but uses less than 10 watts and lasts for 25,000 hours — or 25 times as long
LED alternative to the common 60-watt bulb. Sixty-watt lights account for 50% of the domestic incandescent market; if they were replaced by LED bulbs, the U.S. could save enough electricity per year to light 17.4 million households
We have to pick just one? Impossible... There have been SO many great inventions some of which have been mentioned here, e.g. the wheel, insulin, telephone, penicillin, the bike (of course!), but I think my favourite is the internet. It is such an all encompassing telecommunications device that can be used in SO many different ways. :happy: