LED_(Light_Emitting_Diodes)_Circuits
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1.5 Volt LED Flashers #1: four circuits with description |
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1.5v LED FLASHER: This is a very basic little circuit built around the LM3909 IC. A list of components and values is included. |
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10 Channel LED Sequencer: based on4017 |
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10 LED Sequencer: in PDF format, text in Finnish |
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2 LED Flasher: simple2- transistor circuit which blinks2- LEDs |
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28 LED Clock Timer 72 LED Clock: programmable clock Timer circuit that uses individual LEDs to indicate hours and minutes |
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Alternating LED Blinker uses Four Parts: 03/26/98 EDN-Design
Ideas /Grand Prize Winner1998 |
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Alternating LED Flasher uses Minimal Parts: 11/20/97
EDN-Design Ideas / A pair of alternating flashing LEDs makes an
excellent visual alarm, this alternating LED flasher is based on
one LED with built-in flashing function and tw1o transistors
driving the other normal LED |
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Alternating LEDs Flasher: Mar-03 |
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Analog LED Bar VU Meter: built around discrete components |
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Audio LED VU Meter: built around discrete components |
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Back & Forth Flasher: for16 LEDs |
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Basic LM3909 LED Flasher: runs from1.5-Volt battery |
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Bicycle Back Safety Light: Flashing13 LED unit,3V supply Also suitable for jogger/walkers |
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Buck IC boosts battery voltage for white LED: 04/24/03
EDN-Design Ideas / White-light LEDs are finding their way into
many markets that incandescent bulbs once served. Flashlights
are among the newer applications in which reliability,
ruggedness, and ability to control the power draw of the LEDs
make these devices attractive. With incandescent bulbs, the
power management for the device is a simple on-off switch....
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Car Message Display: CaMeD was designed and built to be used in an automobile. Its purpose is to display various symbols/messages to the car driver traveling behind you. It uses1024 LEDs to form a32 x32 matrix display. A total of12 symbols/messages can be displayed,4 of them being user-definable by using a visual basic utility tool connected to the rs232 port of a PC. |
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Circuit Controls tw1o LEDs With One Microcontroller Port Pin
: 04/01/02 Electronic Design - Ideas for Design /
Microcontroller port pins can typically be driven either high or
low, or else be put into an "input" or high-impedance state.
This circuit uses the three states to drive tw1o separate LEDs
with one port pin. This can be very useful when there are no...
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Circuit drives mixed types and quantities of LEDs:
10/03/2002 EDN - Design Ideas / Portable systems
often use LEDs of different colors and in varying quantities of
each color. Some examples are white for the display backlight,
green for keypad illumination, and red for power. Typically, the
LEDs derive power from at least tw1o power supplies: one for
"standard" LEDs (red and green) and one for white LEDs.. |
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Circuit efficiently switches bipolar LED: 11/22/2001 EDN -
Design Ideas / The circuit in Figure 1 represents one method to
switch a bipolar, tw1o-color LED using an SPDT mechanical switch
or relay. This circuit wastes power and does not work properly
if the power-supply voltage is not substantially more than the
sum of the LEDs` forward voltages. The circuit is, therefore,
marginal, to the point of being unusable, with a 5V supply and a
red or green LED, which... . |
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Create secondary colors from multicolored LEDs: 07/24/03
EDN-Design Ideas / It is well-known that simultaneously mixing
tw1o primary-color light sources, such as red and green, creates
a secondary color, such as yellow. This mixing process commonly
occurs in tricolor LEDs. One disadvantage of this method of
generating a yellow color is that the LED must use tw1ice the
current because both the red and the green LEDs must be on.... |
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Dancing LEDs: A LED sequencer, following the rhythm of music or speech 9 Volt Battery-operated portable unit |
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DualGate Inverter Oscillator Saves Power, Boosts LED Brightness
: 06/24/02 Electronic Design - Ideas for Design / An LED`s
brightness is directly proportional to the current through it,
which creates a challenge for low-voltage and battery-powered
applications. But it`s possible to increase an LED`s brightness
without increasing the system`s power requirements.... |
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Economical Circuit Drives White LEDs: 11/23/00 EDN-Design
Ideas / PDF contains multiple circuits - scroll to find this
circuit.
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Fading LEDs: 2-strips of LEDs fading in a complementary manner 9 Volt Battery-operated portable unit |
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Fading Red Eyes: can be used to slowly illuminate and fade a pair of red LEDs |
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Fantastic Atom Expander: "exploding atom" effect using 98 LEDs |
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Fire Lights: LEDs shimmer randomly as though on fire. Circuit generates true random coin-toss output. |
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Flasher Circuit : LED Flasher, suitable for Christmas Lights |
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Flashing High Intensity LED 3rd Brake Light: This circuit to make a flashing3rd brake light assembly was designed to be easy to locate all the needed components and reasonably in expensive to build. |
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Get More than Three Colors From a Dot Matrix LED : 06/04/98 EDN-Design Ideas |
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Grantronics Projects Christmas Tree : flashes LEDs mounted to Christmas tree shape PCB, kit from kitsrus.com |
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Inexpensive LED Drives Flash & Beep Circuit: 06/05/97 EDN-Design Ideas |
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LED Chaser: simple10 LED chaser |
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LED doubles as emitter and detector: 08/16/2001 EDN - Design
Ideas / Every junction diode exhibits some degree of
photosensitivity when it receives light comprising an
appropriate range of wavelengths. The spectral response of a
junction diode depends on a variety of factors, including
material chemistry, junction depth, and packaging. The packaging
of most devices aims to inhibit sensitivity to radiant flux to
maintain the intended function of the de |
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LED driver combines high speed, precision : 08/21/03
EDN-Design Ideas / Applications such as turbidity measurement
and densitometry require cleanly pulsed light sources with
stable amplitudes. 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 function.... |
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LED driver delivers constant luminosity: 06/12/03
EDN-Design Ideas / The circuit in Figure 1 is similar in
principle to that of a previous Design Idea (Reference 1) but
offers improved, more reproducible performance. The output
current is almost constant over an input-voltage range of 1.2 to
1.5V and is insensitive to variations of transistor gain.
Transistors Q1 and Q2 form an astable flip-flop.... |
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LED Driver Displays Standing Wave Radio: 03/18/99 EDN-Design
Ideas / PDF contains multiple circuits - scroll to find this
circuit
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LED Flasher & TRAC Pulser Work off AC Line: 01/15/98 EDN-Design Ideas |
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LED Flasher indicates Low Battery Condition: 01/02/97 EDN Design Ideas |
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LED Flasher: built using tw1o transistors and some other components |
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LED Headlamps : This article includes circuits of DC-DC LED drivers (click PICs for bigger ones) step downs to run LEDs on less than Battery Volts, Boost for above. |
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LED Light Dimmers uses only tw1o Lines: 03/21/02 EDN-Design
Ideas / PDF contains multiple circuits - scroll to find
the one of interest -- This circuit provides32 steps of
brightness control (from0 to100%) for a backlight or instrument
panel, using just tw1o general-purpose-microprocessor signals.
Although the circuit shows the circuit driving white LEDs, the
load could also be a dc motor or an incandescent lamp. The basis
of the circuit is a modified Schmitt-trigger relaxation
oscillator controlled by MAX5160 digital potentiometer. |
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LED Mood Light: this LED circuit makes a nice lamp that is low power, runs cool, and has a long lifetime, operates from12V, puts out a warm yellow shade of light, the color may be adjusted by changing the number of red or green LED strings |
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LED or Lamp Flasher : Minimum parts counting. Designed for3V battery operation |
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LED or Lamp Pulser : Astonishing effect4.5 Volt supply |
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LED Pilot Light (AC or DC): LED current is constant betw1een 6 and 8 mA at5 to30Vdc |
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LED Sign: uses tw1o LED arrays to form a 7 X 10 matrix. It produces moving messages or animations stored in an EPROM. |
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LED Stroboscope: This simple LED Stroboscope circuit which I designed, maintains constant brightness of the LED at all frequencies. This is accomplished by duty-cycle and pulse width control. It is useful for measuring the speed of motors. It can easily be calibrated using a watch so you don’t need a frequency counter. |
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LED Torch : A white LED torch that consumes just24 mW |
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LEDs Flasher, Alternately: Classic astable multivibrator using2 transistors. Transistor is not critical. Try these:2N4401,2N2222, NTE123A, NTE123AP, NTE159, TUP/TUN and those in your junk box, you may find that most of them will work. |
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Light a white LED from half a cell: 06/12/03
EDN-Design Ideas / Whether you use them as indicators or to
provide illumination, LEDs are hard to beat in efficiency,
reliability, and cost. White LEDs are rapidly gaining popularity
as sources of illumination, as in LCD backlights, but with
forward voltages typically ranging from 3 to 5V, operating them
from a single cell presents obvious difficulties... |
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Light Pollution Meter : LED brightness control circuit and a multimeter to compare light levels to LED level. |
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Linear Constant Current LED Lamp Dimmer: This circuits drives24 white light LEDs with an adjustable constant current. |
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Low Power LED Flasher : based on LM3909 |
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McMurtrie`s Self Powered Flashing LED : circuit which uses a LED as solar panel to charge a capacitor which flashes a LED, the LED will blink when the circuit is placed in bright light |
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Park Aid: 3-LEDs signal bumper-barrier distance Infrared operation, indoor use |
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Propeller Clock: a few light emitting diodes spin, precisely controlled by a PIC microprocessor, giving the illusion of a larger array. |
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Reset Circuit Provides Snappy Action: 04/29/99 EDN-Design
Ideas / PDF contains multiple circuits - scroll to find this
circuit |
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Signal Processor Adds LED Display: 06/05/96 EDN-Design Ideas |
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Simple Logic Probe uses Bicolor LED: 03/13/98 EDN-Design Ideas |
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Single cell lights any LED: 07/05/2001 EDN - Design Ideas /
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,
such as a red LED in an astronomer`s flashlight, which doesn`t
interfere with night vision.. |
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Single FET Controls 2nd LED Array in SwitchMode LED Backlight:
Maxim APP1871: Feb03,2003 / A design in which the display
is backlit (or frontlit) for extended periods needs an efficient
circuit that drives the LEDs with a controlled current, and
eliminates the wasted power associated with current-limiting
resistors. A switch-mode boost design that regulates current
instead of voltage accomplishes this purpose. |
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Single FET Controls LED Array: 04/12/01 EDN-Design Ideas /
PDF contains multiple circuits - scroll to find this circuit. |
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Single LED indicates tw1o Power States: 12/05/96 EDN-Design
Ideas / Uses a single bicolor LED to indicate both power-on and
blown-fuse conditions |
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Special Lighting : experiments with white LEDs |
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tw1o LED Flasher: simple2- transistor circuit which blinks2- LEDs |
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tw1o LEDs Perform Rudimentary Spectral Analysis: 09/01/94 EDN-Design Ideas |
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tw1o Signals Easily Control Tricolor LED: 09/14/95 EDN-Design Ideas |
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Voltage to current converter drives white LEDs: 06/27/2002
EDN - Design Ideas / 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 LED or tw1o series-connected
green LEDs, using only a few components.. |
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White LED drive from 1.5V : Blocking oscillator based design allows LED + power supply to fit in #222 lamp base. |
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White LED driver touts high efficiency: 06/12/03
EDN-Design Ideas / White LEDs, the most recent addition to the
LCD backlight, find common use in providing backlight for color
LCDs. Thanks to their size and white-light output, they appear
in small, portable devices with color displays, such as PDAs and
cellular phones. Like other LEDs, a white LED needs a
constant-current source—typically, on the order of 15 to 20
mA... |
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