It may seem unusual, but solar power has become a popular way to provide power to lighting systems that activate after the sun goes down. From street lights to garden lamps, solar power provides the energy needed to illuminate the darkness late into the night. These lights contain batteries that charge during the day as sunlight hits the solar cells. At night, a photo-resistor detects the absence of light and a circuit board triggers the batteries to discharge and provide power to LED lights, which are efficient and bright.
You can find devices running on solar power in remote places. Several regions use solar panels to generate power for devices like emergency phone systems on the side of roads and transportation signals. These devices usually have battery packs in addition to solar panels so that they work even after darkness falls. Like the solar-powered lighting systems, the cells can provide the electricity needed to recharge the battery packs each day.
Solar power may also lead to you getting a speeding ticket. Some speed cameras along roads rely on solar power during the day. So if you’re caught on camera speeding, you may want to shake your fist at the sun for the fine you’ll have to pay. The alternative is to obey the speed limit in the first place.
One common use of solar technology is out of sight unless you have access to a powerful telescope. Many satellites use solar panels to generate power. Engineers will often mount solar panels on arms that can rotate so that the panels always find the best angle to receive as much sunlight as possible.
Solar power comes in handy in remote locations on Earth as well. Research centers in Antarctica use solar panels during the months when that part of the world receives constant sunlight throughout day and night. When the earth’s tilt moves Antarctica into perpetual night, the facilities depend upon wind turbines to generate power.
As solar panel efficiency increases and the cost of manufacturing the photo-voltaic cells falls, it’s likely that we’ll see many more applications of solar power across the globe. Maybe one day a better question to answer will be “what doesn’t get its energy from the sun?”
source: How Stuff Works