LED Circuits
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The LED driver in Figure 1 illuminates retinal neurons in a biological experiment that has similar requirements. For a given LED at a given current, the intensity is stable, so switching a stable current is a simple and effective way to obtain the needed.... -
Figure 1 shows the relative responsivity and emission spectra for an Infineon (www.infineon.com) SFH409 LED. This infrared GaAs LED has peak emission at 940 nm with a half-peak bandwidth of 50 nm. In detection mode, it peaks at 920 nm with a half-peak....
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Using just four transistors and six resistors, this circuit provides switchable, constant-current drive for an LED and indicates both open- and short-circuit fault conditions (Figure 1). And there`s a bonus, too. Control signal VCONT switches the LED on and....
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Below is a proof of concept circuit which needs improvement. The part values shown will run a high efficiency red LED with a Vf of 1.9V from only 2 nicads, right down to 2 volts. For a white LED you will need more batteries and you must increase the 1.0K.... -
I don`t know why, but people like blinking lights. You see LED chasers everywhere, in TV shows (Knight Rider), movies, and store windows. This schematic is my version of a simple 10 LED chaser. There is no 555 timer used because at my local electronics store.... -
The circuit in Figure 1 provides 32 steps of brightness controlfrom 0 to 100%for a backlight or instrument panel, using just two general-purpose-microprocessor signals. In addition, the circuit requires little board space, because it uses only three SOT-23s....
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The TL082 (Or a TL072 also is OK) Creates an Adjustable Sawtooth Generator. (It also has a Square wave Output, but it isn`t used here.) The Left and Right LED`s are Connected in Series and if this circuit is used on a 12 volt system, and if a person.... -
This project is also an essential part of the expandable analyser to be published soon (or perhaps "eventually"), and one meter circuit is used for each frequency band. There are many other uses for a simple LED VU meter. They are ideal as power meters on.... -
This circuit operates two LED strips in pulsing mode, i.e. one LED strip goes from off state, lights up gradually, then dims gradually, etc. while the other LED strip does the contrary. Each strip can be made up from 2 to 5 LEDs at 9V supply. The two.... -
This design reconfigures the APD-bias IC, IC1, to allow its low-voltage DAC output to modulate the high-voltage, current-sense feedback via a high-voltage-output transconductance stage comprising Q2 and Q3. These two complementary transistors provide....
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Efficiency can be increased by using a germanium transistor at the 33 ohm current sense resistor, and by using a proper torroid core in place of the crappy ferrite bead. Single AA cell powers two LEDs at constant current.... -
For those who dont like microcontroller projects, pretend the micro is a dedicated LED driver IC that just happens to have been designed to control 30 LEDs in the shape of a Heart (what a stroke of luck!). And it wont be declared obsolete just after....
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Here is the schematic, PC board pattern, and parts placement for a "Fantastic Atom Expander". This circuit produces an "exploding atom" effect using 98 LEDs. # The LEDs can be any colour but blue. For a very interesting effect, make one ring red, the next.... -
The LT®3465 white LED driver is ideal for backlight circuits in small, battery-powered portable devices such as cellular phones, PDAs and digital cameras. The LT3465 includes important features such as automatic soft-start to prevent large inrush....
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White LEDs are widely used in small LCD backlight applications for simplicity, high reliability and low cost. However, due to variations in the forward voltage drop of white LEDs, matching the brightness becomes a major design consideration for multiple....
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The circuit forces a current to build up in the L1 coil and the LEDs until the voltage developed across R3 reaches VFB/3.3V. At this point, power switch Q1 turns off, and the magnetizing current keeps circulating in the coil and LEDs, thanks to....
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The circuit in Figure 1 comprises IC1, a Microchip PIC12F675 microcontroller driving IC2, a Kingbright AAF5060PBESEEVG "rainbow" indicator that contains three ultrabright LED chips (red, green, and blue) within one package. Modulating each LED`s duty cycle....
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This is a pocket-sized LED flashlight operating with only one AAA battery. However, the super high luminosity LEDs(blue,green or white) require at least 3.5 volts of forward voltage. This flashlight is boosting input voltage up to operating voltage of a LED.... -
The circuit in Figure 1 uses IC1, the integrated offline Viper22A switching regulator in a constant-current configuration to drive two to eight 1W LEDs. The circuit operates by monitoring the voltage drop across the sense resistor, R6, and uses this voltage....
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The circuit comprises simply the PWM source, capacitor C, and resistors RD and RW. For CMOS circuits, you calculate the open-circuit output voltage as VCONT=D½§VDD, where VCONT is the control circuit`s output voltage, D is the PWM duty cycle, and VDD is....
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The white-LED flasher in Figure 1 offers an alternative approach to a previously published idea (Reference 1). Targeting use in portable appliances and products powered by a single cell, this circuit flashes an LED to provide a highly visible warning....
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The circuit in Figure 1 allows you to light any type of LED from a single cell whose voltage ranges from 1 to 1.5V. This range accommodates alkaline, carbon-zinc, NiCd, or NiMH single cells. The circuit`s principal application is in LED-based flashlights,....
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Most products use multiple LEDs to provide adequate backlight for a display. Because the LED`s brightness depends on its forward current, these multiple diodes commonly connect in series to ensure that the same current flows through each of them. You need....
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The yellow LEDs are on a small PCB, which are easy to remove. On the PCB there is 3 yellow LEDs and 4 diodes. Pictures of the PCB can be seen here : Top-side - Bottom-side. The schematic is as follows : You now remove the 3 LEDs and the 3 normal diodes.... -
You sometimes need to drive a white LED from one 1.5V battery. Unfortunately, the forward voltage of a white LED is 3 to 4V. So, you would need a dc/dc converter to drive the LED from one battery. Using the simple circuit in Figure 1, you can drive one white....
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This circuit was designed on request and can be useful to those whishing to have, say, a red LED illuminated when an appliance is on and a green LED illuminated when the same appliance is off. Any mains operated appliance can be monitored by this circuit,.... -
Figure 1 shows a method for driving all the LEDs with a single driver IC from Catalyst Semiconductor (www.catsemi.com), the CAT32. Power comes from a single lithium-ion battery cell. A FET switch can independently turn off the group of six LEDs. The shutdown....
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The circuit of Figure 1 is designed for portable-power applications that require white LEDs with adjustable, logarithmic dimming levels. The circuit drives as many as four white LEDs from a 3.3V source and adjusts the total LED current from 1 to 106 mA in 64....
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This is a practical white LED head mount lamp (flashlight). Recently many white LED flashlights appear on the market. However, most flashlights require three cells because they are regurating output current with only series resister. The odd number of cells.... -
Figure 1 illustrates one possible approach that uses external inverter IC1 to drive D1, a red/green bidirectional LED. A logic-high output on the port pin forces current through the green (upper) LED and pulls the inverter`s input high, which drives the....
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This circuit operates a LED in pulsing mode, i.e. the LED goes from off state, lights up gradually, then dims gradually, etc. This operation mode is obtained by a triangular wave generator formed by two op-amps contained in a very cheap 8 pin DIL case IC..... -
* Flashing frequency can be varied by changing R1 value in the 1M - 4M7 range. * This circuit is very efficient when driving a small 3.2V incandescent lamp. In this case omit the LED and R3, connecting the bulb across Q2 Collector and positive supply,....
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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