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LED Tachometer with Dual Displays, Pt.1 - A responsive and accurate tachometer is essential for motoring enthusiasts. This new unit features a bright 4-digit display plus a 32-LED circular bargraph. The LED bargraph responds rapidly to changes in RPM while the digital display shows accurate RPM readings with a steady throttle.__ SiliconChip LED Tester - NOTE
: Must register on this site __ Designed by Published in Elecktor July/Aug, 2010
LED Tester - Schematic + Info + pictures __ Designed by Lennie Zink
LED Thermometer - This LED thermometer is designed for in home use, to read temperatures between about 60 and 78 degrees Fahrenheit. It is based around a precision temperature sensor IC, the LM34DZ. This sensor require no calibration and can measure temperatures of between -50F and +300F. While the circuit shown here does not use the full range of that sensor, it can be modified to do so by simply changing the voltage reference to U2 at the sacrifice of precision. __ Designed by Aaron Cake
LED Torch - LEDs are becoming increasingly popular in many lighting applications. White LEDs are now common in torches. Here’s a simple and economical LED torch that operates off two 1.5V cells. For a white...__ Electronics Projects for You
LED Torch - Based on the MAX660, designed to power three 3mm/5mm white LED's from 3V (1.5V min) , intended for replacing incandescent bulbs in small torches. __ Designed by Submitted Andre
LED Torch - A common problem with small torches is the short life-span both of the batteries and the bulb. The average incandescent torch, for instance, consumes around 2 Watts. The LED Torch in Fig.1 consumes just 24 mW, giving it more than80 times longer service from 4 AA alkaline batteries (that is, up to one month's continuous service) __ Designed by Rev Thomas Scarborough
LED Torchs - A LED torch is one of the simplest projects you can build and it's very interesting as it uses a super-bright white LED. In the history of LED production, red LEDs were the first to be invented and their output was so dim you could barely see if they were illuminated. You needed a darkened room to see them at all __ Contact: Collin Mitchell
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 __ Designed by Bill Bowden
LED used for near-IR light - 09/01/98 EDN-Design Ideas NOTE
: File has many circuits, scroll down. You can successfully use LEDs as sources of near-infrared light. However, when you need a source of light with precisely controlled power, a feedback loop is necessary to compensate for the temporal and thermal changes of the LED parameters. Standard LED types come with neither these monitoring detectors nor an external monitoring photodiode to detect part of the emitted light and generate a feedback signal. The situation calls for some mechanical fixture to mount the photodiode. Design by Lukasz Sliwczynski, Marcin Lipinski, Institute of Electronics, Krakow, Poland
LED Volt Meter - Here is a Simple LED Volt meter to Monitor the charge level in Lead Acid Battery or Tubular battery. The terminal voltage of the battery is indicated through a four level LED indicators. The nominal terminal voltage of a Lead Acid battery is 13.8 volts and that of a Tubular battery is 14.8 volts when
LED Voltmeter - Measures voltages up to 199.9V with 0.1V resolution.
LED Voltmeters 20 & 30 LED's - These are Basic Expanded Voltmeters based on the National LM3914 chip. They can be Switched to either Bar or Dot Mode. The 20 LED one has a Minimum 2.5 volt range for Full Scale and it can be adjusted to Much Higher voltage ranges with the input potentiometer. __ Designed by G.L. Chemelec
LED white light bulb - mains powered, no loss power supply, ultra green __ Designed by Thomas Scherrer OZ2CPU
LED Wink Tester for 1.5 Volt Cells - This page contains a collection of circuits that wink when the power switch is thrown to indicated whether the 1.5 volt (and other voltages near 1.5 volts) cell still has a significant charge left. Choose the best one for your application. __ Designed by Dick Cappels
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 __ Contact: Collin Mitchell
LED Blinker uses 4 parts - EDN-Design Ideas March 26, 1998 [ NOTE
: File has multiple design, scroll for this one.] The circuit in Figure 1 is an easy-to-make attention-getter and runs for a week or longer on two AA cells. In September, I used this circuit for a school fundraiser, and it helped me generate more than $100. My dad showed me a circuit in EDN that did the same thing, but it uses more parts (see "Alternating LED flasher uses minimal parts," EDN, Nov 20, 1997, pg 104) . Design by Andy Meng, Cincinnati, OH
Led Strobe 2 - this version has been built and tested and is very simple indeedbased on alien project astable! __ Contact: P. Townshend EduTek Ltd
LED2 LED Sensor Relay Tracker - Circuit 1 tends to chatter the relays under certain lighting conditions as there is no built in hysteresis. This version uses a Schmitt trigger hex inverter circuit to eliminate the chatter. It works better but is more complex __ Contact: Duane C. Johnson
LED3X LED Sensor Electronic Tracker with H-Bridge Drive - The LED3 using surface technics was just to hard to assemble in a timly manor as sales were increasing. I needed a circuit that could be built with mostly through hole components. At the same time, there were other features and enhansments that I thought were needed. This was the impetus for the LED3X series of solar trackers __ Contact: Duane C. Johnson
LED7 Solar Tracker - Schematic only, no circuit description __ Contact: Duane C. Johnson
LED-Based Message Display - This LED-based message display is built around readily available, low cost components. It is easy to fabricate and makes use of 3mm red LEDs. A total of 172 LEDs have been...__ Electronics Projects for You
LED-Based Reading Lamp - This lamp circuit using ultra-bright white LEDs provides sufficient light for reading purposes while consuming approximately 3 watts of power. In the case of AC mains failure, the battery backup circuit...__ Electronics Projects for You
LED-Based Running Display - Here is a circuit that creates an eye-catching running display effect using LEDs. It can be used to light up borders of animations, pictures, etc, and also for short word displays.__ Electronics Projects for You
LED-Current Limiter Accepts AC or Dc - 07/14/11 EDN-Design Ideas Prevent excessive current from overdriving your LEDs. LED drivers have lots of features and require plenty of external components. When your application requires no PWM (pulse-width-modulated) dimming or controlled frequency operation, your primary concern may be that too much current could damage or destroy your LEDs. In this case, you can make a simple LED-current limiter from a common low-dropout linear regulator. The circuit in Figure 1 is an LED light bulb for a landscape-lighting system. Landscape lighting typically operates from 12V ac, and peak voltage is approximately 17V. Because the regulator is in series with the LED string, the LED-string current equals the regulator’s output current. Design by Roger Griswold
LED-flashlight works at voltages as low as 0.5V - 09/23/10 EDN-Design Ideas Extend the life of alkaline batteries. Design by GY Xu, XuMicro, Houston, TX
LEDMATRIX, a 80x32 pixel DIY LED matrix display - The LEDMATRIX additionally includes a simple speaker allowing to e.g. notify the user of a new message being displayed. Furthermore a TSOP1736 IR receiver can optionally be connected. This device receives and decodes the IR signals used by ordinary TV remote controls. By returning informtion about received IR signals to the controlling PC, the displays contents may e.g. be remotely changed using a simple spare IR remote control. __ Designed by Till Harbaum <Till @ Harbaum.org>
LED_Flameless_Candle_Power_Boost - Most flameless candles are now quite simple circuits. They consist of nothing more than a power switch, a battery and a special flickering LED. The special LED might work fine for a candle but it is not bright enough for the touch. To boost the power of this flickering device, you can remove that LED from a flameless candle and insert into the circuit shown below. This circuit extracts the flickering signal from the special LED and uses the signal to drive 5 super bright yellow LEDs at a peak current of 20ma each. . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 13 Nov 2010
LEDs Flasher Alternately - Classic astable multivibrator using 2 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. __ Designed by Tony van Roon VA3AVR
LEDs Indicate Sound Level - 08/25/11 EDN-Design Ideas Build a battery-operated portable meter to measure sound-pressure levels. This Design Idea describes a battery-operated, portable soundlevel meter (Figure 1) . Its portability makes it useful for detecting the source of noise in automotive engines and power trains, factory machinery, and residential HVAC (heating/ventilation/air-conditioning) systems Design by Stephen Kamichik, Ile Bizard, PQ, Canada
LED_Light_for_Tool_Shed - I have a lean-to 8ft by 12ft shed next to my house. It is full of lawn chemicals and garden supplies. There were times when I needed to get something from inside the shed during the dead of night. Early on I had to use a flashlight. But later, I installed a series of five 12v LED light strips on the ceiling. Each strip contained 15 3v white LEDs. The strip had 5 strings of three LEDs, wired in series, with a 150 ohm current limiting resistor. . . . Hobby Circuit by David Johnson P.E.-July, 2017
LEDs Light LAN-Cable Tester - 12/02/10 EDN-Design Ideas A series of LEDs indicate the health of an Ethernet cable. [Design Ideas by Noureddine Benabadji, University of Sciences and Technology, Oran, Algeria Design by Noureddine Benabadji, University of Sciences and Technology, Oran, Algeria
LEDs Light Up Digital POV Clock - 1-Apr-11 -Design News: Steve RavetThis gadget, created with a dead hard drive, flashes softly glowing green digits. __ Gadget Freak
LEDs or Lamps Sequencer - Very simple, versatile modular design No limits to the number of modules used in the ring __ Contact: Flavio Dellepiane, fladello @ tin.it
LEDs used as Photodiodes - 11/18/10 EDN-Design Ideas Ambient light changes an LED's resistance, making it act like a photodiode. [Design Idea by Raju R Baddi, Raman Research Institute, Bangalore, India Design by Raju R Baddi, Raman Research Institute, Bangalore, India
Left-Right Right-Left Running Lights - Our ROCKERUD6 has many applications; fill your party with running, blinking ROCKERS. Mount the ROCKER on your bicycle so you'll be more visible and have a safer ride when signaling. Use as a sign on room door as an indicator of how way "cool" you are. Place ROCKER anywhere you’d like to draw attention and a smile. The unique small design will allow you to mount it almost anywhere. Operate it with 9V battery, 12V car battery, four 1.5V batteries, or via one of our battery simulator kits. __ Contact: Kit from Elich Industrial Development, Corp Lighthouse_Solar_Powered - While at a discount store one day, I spotted an interesting tall lighthouse. It had a tiny solar panel and an equally tiny LED light. The LED was pointing downward, at the center of a rotating light reflector. I thought it might be turned into an interesting addition to my wife’s garden. . . . Hobby Circuit by David Johnson P.E.-September, 2017 |
