LED Circuits
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Maxim/Dallas > Designer`s Library > App Notes > DISPLAY DRIVERS Keywords: Single FET Controls 2nd LED Array in Switch-Mode LED Backlight Related Parts APP 1871: Feb 03, 2003 Download, PDF FormatDownload, PDF Format (29kB) APPLICATION.... -
This deceptively simple sequencer actually pulse width modulates the LEDs as it fades from one LED to the next. Bulbs will last much longer when driven in this gentle manner. Add MOSFETs or transistors to the outputs if you wish to drive bulbs. You can.... -
The LED Torch is based on a 7555 timer running in astable mode (do not use an ordinary 555). A white LED (Maplin order code NR73) produces 400 mcd light output, which, when focussed, can illuminate objects at 30 metres. Try Conrad Electronic for what appears.... -
High power LEDs are quickly expanding their reach as the lightsource of choice for flat panel computer and TV monitors, TV projection, signage, portable lights and automotive interior, trim and brake lighting. The input voltage and LED voltage....
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The LTC3205 is a highly integrated multidisplay LED controller. The part contains a high efficiency, low noise fractional step-up/step-down charge pump to provide power for both main and sub white LED displays plus an RGB color LED display. The LTC3205.... -
The LM317L and resistor act as a current regulator set to 40ma. Current flows from the battery through one pair of LEDs, through the regulator, through the other pair of LEDs, and back to the battery. The capacitor filters out noise on the power supply.... -
The circuit`s 90% conversion efficiency offers a distinct power-saving advantage over resistor-limited and linearly regulated designs. It might appear that a series-LED connection is unsuitable for applications in which some (but not all) LEDs must be off. A....
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The LTC3453 is a synchronous buck-boost DC/DC converter optimized for driving up to 4 white LEDs at a combined current of up to 500mA from a single Li-Ion battery input. The regulator operates in either synchronous buck, synchronous boost, or buck-boost.... -
The LT®1937 is a step-up DC/DC converter specifically designed to drive white LEDs with a constant current. The device can drive two, three or four LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents resulting in.... -
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.... -
Using inexpensive components, you can fit a simple probe circuit into a pencil-sized enclosure. When both LEDs are on, the probe indicates the presence of an ac voltage; either LED alone indicates the presence and polarity of a dc voltage. The diode-bridge.... -
A minimum number of parts yields a compact switching converter that can provide sufficient voltage to drive white LEDs. The resulting lamp is much more efficient, in terms of lumen hours per pound of battery, than incandescent bulbs, and because the color of.... -
The operating voltage of white LEDs coupled with my emotional need for low cost for a given function, motivates me to make LED drivers suitable for battery operated lanterns that can run from a small number of cells. White and Ultraviolet LEDs available at.... -
Finally, white LED`s are bright enough to use in a practical stroboscope. This circuit can operate as a bench-top stroboscope that, in conjunction with an oscilloscope or frequency meter and bench top power supply can accurately measure rotational speeds, or.... -
Photo. This is the test circuit -the basic driver is only two transistors, two resistors, the circuit was evaluated using a white LED, but when it was time to button it up and archive it, I replaced the expensive white LED with a cheap green one... -
Each time switch S1 is closed the count on the CD4017 advances by 1 step and the coresponding LED turns on. When the maximium count plus 1 is reached for each circuit the cycle is restarted and repeats... -
These circuits provide a means of altering the YELLOW output of RED / GREEN type two colour light emitting diodes. These circuits use the LM555 timer chip... -
This circuit when used with a 555 timer will cause light emitting diodes to turn on and off more slowly. This will make the LEDs appear similar to incandescent lamps... -
The circuit uses independent timers to flash two light emitting diodes. Any time that light emitting diode D1 is lit__light emitting diode D2 will be switched off. Light emitting diode D3 is on if both D1 and D2 are off. Two versions of the circuit are.... -
This may well be the world`s only discreet logic circuit to generate truely random output. It makes an excellent candle flicker light for your haloween pumpkin, and looks much more authentic than a shimmer light wherever a good a simulated flame effect is.... -
This is a very simple project using a printed circuit board and 8 components. It will flash an ordinary 3mm or 5mm (1/8" or 1/4") LED at a rate of about one flash per second. This circuit works on the basis of a high-gain amplifier being driven into.... -
The circuit consists of two building blocks. The first is a square wave oscillator made up of two transistors in a multivibrator arrangement and the second is a CD 4017 decade counter IC. The multivibrator contains two extra components to speed up the.... -
This circuit is usable as a Night Lamp when a wall mains socket is not available to plug-in an ever running small neon lamp device. In order to ensure minimum battery consumption, one 1.5V cell is used, and a simple voltage doubler drives a pulsating.... -
Very simple, versatile modular design. The purpose of this circuit was to create a ring in which LEDs or Lamps illuminate sequentially. Its main feature is a high versatility: you can build a loop containing any number of LEDs or Lamps, as each illuminating.... -
# This version uses a double sided PCB. Dimensions are approximately the same as the original version. # Removed the second push button switch and components for the RS232 serial interface. # Added 22K resistor between MCLR input and Vdd. This....
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This project is a 4 channel DMX512 driver board. It features four power MOSFETs that can be configured to operate in PWM mode or as on/off outputs. The driver can be configured to use any four consecutive addresses across the full 512 channel address....
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The heart of the circuit is a string of 10 white LEDs. These are wired in series and connected to a current-regulated step-up switching power supply circuit. DC powered LED lighting circuits can vary from the trivial, with a single LED and a series resistor,.... -
This circuit makes a nice lamp that consumes little power, runs cool, and has an incredibly long lifetime. The lamp puts out a warm yellow shade of light, the color may be adjusted by changing the number of red or green LED strings. Operating Voltage: 12V DC.... -
The RGB LED driver described on this page uses logic level 'N' channel MOSFETs which allow it to control LED arrays or lamps at up to 5 amps per channel without heatsinks. The driver uses exactly the same firmware as the small RGB LED driver shown in the....
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The circuit uses (RGB) Red, Green and Blue high brightness LEDs that are pulse width modulated (PWM) to vary the intensity of each colour LED. This allows effectively any colour to be generated with rapid changing strobe effects, fast and slow colour fades....
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This neat little circuit provides 8 LEDs directly driven from the PIC along with a single mode control switch. The firmware elsewhere on this page drives the LEDs with a 5 bit PWM signal providing each of the 8 LED channels with four levels of intensity;....
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This simple circuit functions as a 12 LED chaser. A single illuminated LED 'walks' left and right in a repeating sequence, similar to the effect seen on KITT, the car in the Knight Rider TV series. Fully commented source code and programmer ready HEX....
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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