Resistor Chip Arrays
Product name: LED Dimming Electronics Soldering Kit
Model number: TJ-56-616
Board size: 83*59mm
Power supply: ± 12V (DC power supply)
Product Description
This project is the installation and commissioning of a PMW LED dimming lamp circuit. As a new and most promising light source, LED lighting with its energy saving and environmental advantages is gaining more and more attention, coupled with national and local government policies to encourage, China's LED lighting industry into a rapid development stage, the market is growing rapidly. In indoor lighting, the use of LED instead of traditional dimmable incandescent or halogen lamps will also be the general trend. The two main types of dimming methods for switching mode regulator powered LEDs are PWM and analogue methods, where PWM dimming can significantly reduce the colour variation of LEDs.
Working Principle
The LM7812 and LM7912 form a ±12V dual power supply to power the PMW LED dimming circuit. The operational amplifiers U 1A and U1B form a square wave and triangle wave generation circuit, which outputs a triangle wave at pin 1 of U1 to pin 6 of U2 for comparison with the DC potential at pin 5 of U2. The value of U2's pin 5 potential determines the pulse width of its pin 7 output square wave, i.e. PMW modulation. The wider the pulse width, the longer the time in a cycle behind the transistor on, the brighter the LED light; the smaller the pulse width, the shorter the time in a cycle of transistor on, the darker the LED light. And U2's 5-pin potential depends on the U2A voltage follower input voltage, the size of the input voltage is adjustable resistor RP1 to adjust, adjust RP1 can control the brightness of the LED light.
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Hign-concerned Chemical : None
Type : Voltage Regulator
Origin : Mainland China