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LED or Incadescent 12 Volt Lamp Fader - (electronic circuit added 6/07)
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LED or Lamp Flasher - Minimum parts counting. Designed for3V battery operation
(added 9/04) |
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LED or Lamp Pulser - Astonishing effect4.5 Volt supply (added 9/04) |
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LED Oscilloscope - George Katz of Balgowlah Boys high in Sydney presented a
solid state oscilloscope. He says "probably the best advantage is its very small
size and the fact that it can run off the power supply of the circuit being
tested. Although it has a low frequency range, it can still be used for most
circuits. Its poor resolution will still allow for most waveforms to be
visualized." ….(electronic schematic added 11/08) |
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LED Oscilloscope 1 - Uses a matrix of 100 LED as a display (circuit added
11/06) |
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LED Photo Sensor Circuit - Here's a circuit that takes advantage of the
photo-voltaic voltage of an ordinary LED. The LED voltage is buffered by a
junction FET transistor and then applied to the inverting input of an op-amp with
a gain of about 20. This produces a change of about 5 volts at the output from
darkness to bright light. The 100K potentiometer can be set so that the output is
around 7 volts in darkness and falls to about 2 volts in bright light... (added
4/05) |
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LED Photodetector - Using the light-emitting diode as the photodetector
(circuit added 11/06) |
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LED Pilot Light AC or DC - LED current is constant between 6 and 8 mA at5
to30Vdc (Tony van Roon's electronic design added 4/02) |
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LED power meter - Used for testing RF transmitters (electronic circuit
added 05/07) |
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LED Relay Timer - This circuit provides a visual 9 second delay using a 7
segment digital readout LED. When the switch is closed, the CD4010 up/down counter
is preset to 9 and the 555 timer is disabLED with the output held high. When the
switch is opened,....(circuit / schematic design added 6/06) |
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LED RF Signal Meter - (circuit added 6/07) |
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LED senses & displays ambient light intensity - 11/09/06 EDN-Design Ideas: LED
doubles as photosensor and visual indicator of ambient-light intensity.....(design
idea added 05/07) |
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LED senses & displays ambient light intensity (video) - (Video Design Ideas-
EDN, 09/05/07) -- Dhananjay V Gadre of India's Netaji Subhas Institute of
Technology explains how an LED can double as a photosensor and a visual indicator
of ambient-light intensity. (electronic design idea added 09/08) |
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LED Sequencer - The model 4017 integrated circuit is a CMOS counter with ten
output terminals. One of these ten terminals will be in a "high" state at any
given time, with all others being "low," giving a "one-of-ten" output sequence. If
low-to-high voltage pulses are applied to the "clock" (Clk) terminal of the 4017,
it will increment its count, forcing the next output into a "high" state...
(circuit added 6/07) |
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LED shine - If you wish to have some really nice looking LED's shining out of
your equipment panel, you may try the following trick: pass repeatedly a fine
sandpaper on the surface of any transparent and clear LED until the same …
(added 9/07) |
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LED Sign - uses two LED arrays to form a 7 X 10 matrix. It produces moving
messages or animations stored in an EPROM. (added 7/03) |
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LED Strobe - This circuit drives a high brightness LED as a strobe. The
BD136 (I had one spare) transistor can be used to drive an LED from a higher
voltage source than the PIC operates from if required…. (added 6/06) |
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LED strobe has independent delay & duration - 06/11/09 EDN- Design Ideas,
High-brightness LEDs, with independent delay and duration, find use in a
visual-inspection application.....(design idea added 08/09) |
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LED Stroboscope - This simple LED Stroboscope circuit which I designed,
maintains constant |
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LED Torch - A white LED torch that consumes just24 mW (added 4/02) |
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LED Torch Circuits - (design added 04/08) |
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LED Traffic Lights - The LED traffic Light circuit controls 6 LEDs (red,
yellow and green) for both north/south directions and east/west directions. The
timing sequence is generated using a CMOS 4017 decade counter and a 555 timer.
Counter outputs 1 through 4 are wire ORed using 4 diodes so that the (Red,
North/South) and (Green, East/West) LEDs will be on during(electronic circuit
added 4/05) |
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LED Voltage Indicator - This teensy little board is only 1 inch (25mm) square,
and is handy as a combined power on and low battery voltage indicator. The two
colour LED changes from green to red when the battery voltage drops below the
adjustable trigger voltage. It's usable between about 6V and 30VDC, and uses a
precision LM336Z-2.5 voltage reference. The LED can be reversed so it changes from
green to red if the preset voltage is exceeded, if required. (circuits added
09/05) |
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LED Voltmeter - Measures voltages up to 199.9V with 0.1V resolution.
(circuit added 8/06) |
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LED Voltmeter Expanded Scale (ideal for your car) - Its Useful to see the
charge voltage. This Helps in detecting a Bad Alternator before it creates a
dead battery....(electronic schematic added 12/08) |
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LED VU Meter - The circuit is completely conventional, and is based on the
application notes from National Semiconductor. The circuit is shown in Figure 1
and as you can see it uses a single IC and a few discrete components. The extra
diode (D3) is included to ensure that the DC to the LEDs is almost unfiltered.....
(schematic added 6/07) |
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LED Zeppelin - The name of our game, LED Zeppelin, is a play on words. It
comes not from the pop group of the same name but from Graf Von Zeppelin, a German
who invented the first rigid air ship in 1900. The association fits
perfectly. The game consists of six LEDs and an indicator LED that flashes at a
rate of about 2 cycles per second. A push button is the "Operations Control" and
by carefully pushing the button in synchronisation with the flashing LED, the row
of LEDs will gradually light up....(electronic circuit added 2/07) |
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LED7 Solar Tracker - (electronic circuit added 7/03) |
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LED-Based Message Display - (electronic Circuit / Schematic added 10/04) |
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LED-Current Limiting Resistor Calculator - The calculators on this page can be
used to find current limiting resistors and currents for Light Emitting Diodes.
(04/05/07 |
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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.
(Tony van Roon's electronic design added 4/02) |
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LEDs or Lamps Sequencer - Very simple, versatile modular design No limits to
the number of modules used in the ring (added 9/04) |
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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.....(design idea added 1/05) |
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Light Pollution Meter - LED brightness control circuit and a millimeter to
compare light levels to LED level. (added 6/07) |
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Lighthouse LED Flasher - This was originally designed for a model in a HO
train set. It simulates the behavior of the light from a lighthouse.
The LED intensity gradually increases, then flashes with a bright light and
finally decreases slowly in intensity. ….(designed by David A. Johnson) |
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Lighting Management System for Six White LEDs & One RGB or Flash LEDs -
National Semiconductor Application Note LP3936 June 2004 (app note added 02/05) |
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Lighting Management System for Six White LEDs & Two RGB or Flash LEDs -
National Semiconductor Application Note LP3933 March 2004 (app note added 02/05) |
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Line powered driver lights up high power LEDs - 06/08/06 EDN-Design Ideas: LED
array reduces power and maintenance expenses.....(design idea added 11/06) |
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Line Powered White LEDs - The LED circuit above is an example of using 25
white LEDs in series connected to the 120VAC line. It can be modified for more or
less LEDs by changing the R value. The exact resistance value will depend on the
particular LEDs used. In operation, a DC voltage of around 170 is produced from
the bridge rectifier and 50uF capacitor. The capacitor value is not critical
...(electronic circuit added 1/06) |
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Linear brightness Controller for LEDs has 64 taps - 03/15/07 EDN-Design Ideas:
Digital potentiometer controls the brightness of LEDs.....(design idea added 9/08) |
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Linear Constant Current LED Lamp Dimmer - This circuits drives24 white light
LEDs with an adjustable constant current. (added 4/02) |
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LM27961-Dual-Display White LED Driver with 3/2x Switched Capacitor Boost -
National Semiconductor Application Note (app note added 2/06) |
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LM3485 LED Demo Board - National Semiconductor Application Note (app
note added 2/06) |
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LM3570: Low Noise White LED Driver System - National Semiconductor Application
Note (app note added 2/06) |
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LM3909 LED flasher - uses an LM3909 LED flasher (Tony van Roon's circuit
design added 04/05/06) |
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LM3909 replacement information - This page features a replacement circuit for
the LM3909 LED Flasher / Oscillator. The replacement circuit uses discrete
components and is essentially the same as the internal circuit of the LM3909. |
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LM555 LED Blinker Circuits - (diagram added 05/07) |
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Logic Probe uses Bicolor Led - 03/13/98 EDN-Design Ideas: (design idea added
03/03/03) |
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Low Noise White LED Driver System - National Semiconductor Application Note
(app note added 07/08/09) |
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Low Power Blink LED - ….(electronic schematic added 08/08) |
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Low Power LED Flasher - based on LM3909 (added 4/02) |
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Low Power LED Voltmeter - This is a low power voltmeter circuit that can be
used with alternative energy systems that run on 12 and 24 volt batteries. The
voltmeter is an expanded scale type that indicates small voltage steps over the 10
to 16 volt range for 12 volt batteries and over the 22 to 32 volt ....(circuit
6/07) |
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low power, long life LED flashlight circuit - Scouring the Internet for
information on LEDs, I accidentally stumbled upon a PDF detailing a flashlight
made from PVC. For the torch, he biases ultra-bright LEDs with ballast resistors
as described in my LED lighting guide. This is a simple solution, but a with a
slightly more complicated circuit we can extend battery life by over ten
times!...(project added 6/07) |
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LT3465-1.2MHz White LED Step-Up Converters with Built-In Schottky in ThinSOT -
Linear Technology LT3465 Switching Regulator (app note added 6/06) |
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LX1995 LED Driver: Camera Flash Application AN-30 - Application Note 30 from
Microsem (app note added 6/06) |
