LEDs are used as indicator in many usages and are frequently used for lighting. Emerging as practical electronic components in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.
In electronics, the basic LED circuit is an electric power circuit used to power a LED. With the adjustable output current, the LED driver circuit ensures users to make detailed modification. Easy-to-drive high power LEDs in series are connected to the device.
The simplest circuit consists of a voltage source powering two components connected in series: A current limiting resistor and LED. Optionally, a switch may be introduced to open and close the LED driver circuit. The switch may be replaced with another component or circuit to form a continuity tester. Albeit simple, this circuit is not necessarily the most energy efficient circuit to drive an LED, since energy is lost in the resistor
Light-emitting diodes are used in applications as diverse as aviation lighting, automotive lighting, advertising, general lighting, and traffic signals. LEDs have allowed new text, video displays, and sensors to be developed, while their high switching rates are also useful in advanced communications technology. Infrared LEDs are also used in the remote control units of many commercial products including televisions, DVD players and other domestic appliances. LEDs are also used in seven-segment display.