At LED on 1960s to 80s before the advent of 10 years, L […]
At LED on 1960s to 80s before the advent of 10 years, LED only red, yellow and green colors, light emitting efficiency is very low (about 1 lm/W), the brightness is relatively low, and the price is high, people just to be used as the indicator of electronic products. From the point of view of LED development and application, this period is the indication application stage of LED.
1 、AC power indicator
. As long as the circuit is connected to the AC power line of the 220V/50Hz, the LED will be lighted to indicate the power on. The resistance value of current limiting resistor R is 220V/IF.
2 、AC switch indicator light
With LED for incandescent lamp switch indicator circuit, when the switch is broken, the bulb is extinguished, the current through the R, LED and bulb EL loop, LED light, convenient for people to find the switch in the dark. At this point, the current in the loop is very small and the bulb won't turn on. When the switch is switched on, the light bulb is lit, and the LED is extinguished.
3、 AC power outlet indicator light
Circuit for AC power socket indicator light using two-color (common cathode) LED. The power supply of the socket is controlled by the switch S. When the red light is LED, the socket has no electricity; when the green light is LED, the socket is electrically charged.
4 、fuse indicator
LED used as electric factory equipment distribution box fuseholders indicator. When the hose is in good condition, the LED is not lit; when the fuse is blown, the LED will be lighted to indicate which fuse the user has blown to replace it. This is very convenient for a porcelain core fuse that can not be observed by the naked eye.
5 、LED advertising signs light
6 、LED monochrome or color display
General monochrome display used to display single line Chinese characters, color display screen for outdoor large screen tv.
7、 LED street lamp
8、 LED car lights and LED electric car lights