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This is the first example that you should to know how to set output pin. In this example, GPO is set as an output. LED1 will be turn-on when GP0 is set high and LED1 wiil be turn-off when GP0 is set low. This example use 4MHz internal clock.

In this page we will introduce a great project designed by Toon Beerten. This project can become a very interesting add-on for your room that's absolutely sure it will impress everyone. As you can see on the photos, we talk about a color fading lamp, that looks amazing! The purpose of this page is to try to give some hints building it successful. This high power led mood light is based on PIC16F628 and the ability of this mcu to produce PWM pulses. Varying pulse width we can produce millions of color combinations using only the three basic colors. So only one RGB (Red-Green-Blue) led is capable producing a rainbow of fading colors. With the help of four switches we can handle all functions of the lamp. We can choose fading or jumping between colors, we can select a rainbow style or a random color changing behavior, we can choose slow or fast changing of colors and we can pause on a desired color. Finally we will make some power dissipation measurements to help us select an appropriate power supply unit.

The circuit to light LED with single 1.5V battery is usually based on a blocking oscillator or a charge-pumped voltage doubler.This is another (but similar to charge pump) way to flash LED with 1.5V battery. The base-R voltage becomes nearly double the Vcc while making oscillation timing of astable multivibrator. LED can be flashed if it is attached aside. Since the LED discharges the C electricity, oscillator timing is shortened.

Using light effects for decoration on festive occasions is a normal practice. Designers are coming up with varieties of electronic circuits to fill the imagination of users. Here is an easy-to-assemble circuit for Christmas decoration as shown in Fig.1. It comprises four transistors, eighteen LEDs, a few resistors and two capacitors.

This is a simple LED torch circuit based on IC MAX660 from MAXIM semiconductors. The MAX 660 is a CMOS type monolithic type voltage converter IC. The IC can easily drive three extra bright white LEDs. The LED's are connected in parallel to the output pin 8 of the IC. The circuit has good battery life. The switch S1 can be a push to ON switch.

Here is a low-cost circuit of Christmas star that can be easily constructed even by a novice. The main advantage of this circuit is that it doesn’t require any step-down transformer or ICs. Components like resistors R1 and R2.capacitors C1, C2, and C3, diodes D1 and D2, and zener ZD1 are used to develop a fairly steady 5V DC supply voltage that provides the required current to operate the multivibrator circuit and trigger triac BT136 via LED1.

There is a major advantage to using LEDs for lighting: various dimming techniques allow seamless control of the light output from the LED source. While LEDs are efficient light sources, the dimming feature also allows for considerable power savings. Control over the light output also helps to set the desired ambience. PWM dimming is preferred to analog dimming for several reasons. For many applications PWM dimming maintains the color of the light output regardless of the dim level. For circuit design, PWM control is more immune to noise; the control signal need not be accurate in both voltage levels and dimming frequency; and the driver circuit design is less complex. PWM dimming usually requires a control line that carries the PWM dimming signal, in addition to the two power-supply lines. This standard configuration is, however, a drawback for applications that use common dimming for a large number of lights; the configuration also makes it difficult to replace the incandescent light installations with two-wire supply lines that depend on supply chopping for dimming control. Traditional, crude LED driver circuits that work with power-supply dimming are problematic. Those drivers turn off power to the LEDs gradually as the input filter capacitors discharge to the minimum operating voltage of the driver. That process can cause the input and output filter capacitors to discharge to low levels. Then when the supply is turned back on, a huge surge of current flows to replenish the capacitor charge, thus causing EMI issues and premature dimmer damage. To prevent these various issues, those circuits use large inductor filters that increase cost. The LED driver reference design described here addresses this basic design challenge with PWM dimming. This LED driver implements PWM dimming based on supply chopping; it does not cause any supply current overshoot. The design provides up to 90% efficiency while operating from a 24V supply. It allows a unidirectional supply input with an efficient semi-MOSFET bridge rectifier at the input. Figure 1 shows the top view of the design board.

Here's a really simple and inexpensive Power LED driver circuit. The circuit is a "constant current source", which means that it keeps the LED brightness constant no matter what power supply you use or surrounding environmental conditions you subject the LED's to. Or to put in another way: "this is better than using a resistor". It's more consistent, more efficient, and more flexible. It's ideal for High-power LED's especially, and can be used for any number and configuration of normal or high-power LED's with any type of power supply. As a simple project, i've built the driver circuit and connected it to a high-power LED and a power-brick, making a plug-in light. Power LED's are now around $3, so this is a very inexpensive project with many uses, and you can easily change it to use more LED's, batteries, etc.

Power RGB is the extension of tinyRGB to drive high power LED’s. For this project I used a 3 x 1W common Anode RGB LED. Q1 to Q3 are N-Channel HEXFet Mosfet’s with logic level drive and a RDSon at about 50mOhms. R1 to R3 are at about 2k2, R4 to R6 at about 15k and R7 to R9 depend on the LED used and VCC. If you use FET’s with higher RDSon you have to consider RDS in your calculation! Rx = (Vcc-Vf)/Im – RDSon [Vcc: Volatge of power supply, Vf: Vorward Voltage of the Diode, Im: Max current of LED]

Power RGB LED Controller is the extension of tiny RGB to drive high power LED’s. For this project I used a 3 x 1W common Anode RGB LED. Q1 to Q3 are N-Channel HEXFet Mosfet’s with logic level drive and a RDSon at about 50mOhms. R1 to R3 are at about 2k2, R4 to R6 at about 15k and R7 to R9 depend on the LED used and VCC. If you use FET’s with higher RDSon you have to consider RDS in your calculation!