But current can not increase indefinitely. Due to the internal resistance of the semiconductor and pn-junction diode will overheat and fail. 5. Why use led? In LEDs, unlike incandescent or fluorescent lamps, electric current is converted directly into light radiation, and it is theoretically possible make almost no losses. Indeed, the led (with proper heatsink), little heat, which makes it indispensable for some applications. Further, the led emits in a narrow part of the spectrum, the color is pure, that is especially appreciated designers, and ultraviolet and infrared radiation, are generally lacking. led is mechanically robust and extremely reliable and its service life can reach 100 thousand hours, which is almost 100 times more than incandescent bulbs, and a 5 – 10 times greater than that fluorescent lamp. Finally, the led – a low-voltage electrical appliance, and therefore, safe.
6. What's wrong with the led? Only one thing – price. So far, the price per lumen, led emission is 100 times higher than a halogen lamp. But experts say that in the next 2 – 3 years this figure will be reduced by 10 times. 7. When LEDs came into use for lighting? Initially, the LEDs were used solely for display. To make them suitable for lighting, it was necessary to first learn how to make white LEDs, as well as to increase their brightness, or rather light output, ie the ratio of luminous flux to the energy consumed. In the 60's and 70's were created LEDs based on gallium phosphide and gallium arsenide, emitting a yellowish-green, yellow and red spectral regions.