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Light Emitting Diodes (LED) Circuits
LEDs:   #'s - B     C - G      H - L       M - P       Q - T     U - Z 
 

Last Updated: October 24, 2017 05:16 PM

Circuits Designed by Dave Johnson, P.E. :

Miniature Lighthouse Light SimulatorThe circuit I came up with is shown below.  It uses two dual low power op amps.  The first two devices form a classic oscillator circuit whose output is a triangle waveform signal.  That signal is routed to a current regulator circuit, which converts the triangle voltage signal to a triangle current signal through the lighthouse LED.  A third op amp generates pulses timed so they occur at the peak of the triangle waveform.  The result is a LED, which gradually grows brighter, then flashes even brighter before dimming again.  This should produce a light, which simulates a rotating lighthouse lightCircuit Solution by Dave Johnson P.E.-May, 2006

Mason_Jar_Solar_Light -  I have modified several commercial solar garden lights over the years.  I switch out the LED, solar panel, battery pack and control circuit.  The result is a much better overall light.  One of my disappointments in using store-bought garden light assemblies is their construction.  They are built so cheaply that over time, water and insects get inside, killing the light operation. . . . Hobby Circuit by David Johnson P.E.-September, 2017

Model Airplane Wing Tip FlasherThe circuit below is designed to flash two white LEDs mounted at the wing tips of a model airplane.  The flasher unit is powered by a 4.5v supply made of three AA or AAA 1.5v alkaline battery cells.  The average current is about 2ma so a set of batteries . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2009

Model Train Lighthouse Flasher RevisitedHO train sets often have authentic looking scale model homes and buildings.    A while back someone asked me to design a flashing LED light, which he could mount inside a model lighthouse and have it operate so it would appear to rotate and flash.    I designed a working circuit but I was never pleased with the results.    I’m still not 100% pleased but the revised circuit below seems to operate a bit better than the older circuit.  … [ . . . Hobby Circuit designed by Dave Johnson P.  E.  , May 2012] . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2012

Modified 4 D Cell LED Lantern -  While shopping at a sporting goods store one day, I spotted a compact LED lantern.  It looked like the kind of lantern I could modify. The lantern LEDs were grouped into three sections of 7 LEDs each, oriented into 120 degree angles.  The LEDs were standard T 1-3/4 epoxy types.  The lantern had a three mode switch which selected between off, full power and half power modes.  At the half power mode, only half of the 21 LEDs were illuminated.  At full power all LEDs were illuminated. . . . Circuit by David Johnson P.E.-September, 2017

Modified Colman Lantern3 -  While shopping at a sporting goods store one day, I spotted a compact LED lantern.  It looked like the kind of lantern I could modify. The lantern LEDs were grouped into three sections of 7 LEDs each, oriented into 120 degree angles.  The LEDs were standard T 1-3/4 epoxy types.  The lantern had a three mode switch which selected between off, full power and half power modes.  At the half power mode, only half of the 21 LEDs were illuminated.  At full power all LEDs were illuminated. . . . Circuit by David Johnson P.E.-September, 2017

Modified LED Night LightI bought some night lights a few months ago from Walmart here in Denver.  The devices were made by Elumina Lighting Technologies Inc.  (www.  eluminalighting.  com) , their model LED-6200A.  I think I paid about $15 for a pack of three lights.  I wanted a light . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2007

Negative 0.5 Volt SupplyThis simple circuit consists of two LEDs and a photo diode.  It generates a negative voltage with a current level of a couple milliamps.  It is ideal for supplying a negative rail to low power “rail to rail” op amp circuits, which need to have a true zero volts output.  Note:  This circuit is not particularly efficient . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006

Night Light from White LEDAs many of you know, I have a pet peeve with poorly made LED night lights.  Often, the light from the LED quickly fades, so within months, the light is useless.  I have posted several versions of modified night lights using higher quality components. . . Circuit by David A. Johnson P.E.-November, 2008

Night_Light_with_20_LED -  After 3 years of continuous 24/7 operation I noticed that the 20 LED array I was using as a night light next to my back door was fading.  Some of the LEDs were much dimmer than others.  I figured that over time, the internal heat dissipated from the LED chip was causing the LED light intensity to fade.  I decided it was time to replace the light. . . . Hobby Circuit by David Johnson P.E.-July, 2017

Nine-Volt Battery Voltage MonitorThis circuit turns on a LED whenever the voltage of a standard 9v battery connected to the circuit drops below 7.2 volts.  It uses a LTC1440 comparator, which also contains a 1.18v reference diode.  In standby mode, the circuit draws only 4uA. . . Circuit by David Johnson P.E.-July, 2006


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Magic Lights -  The circuit as shown in the figure employs 14 bi-colour  (red and green) LEDs having three terminals each.  Different dancing colour patterns are produced using this circuit since each LED can...__ Electronics Projects for You

Make a Joule Thief -  It's a little wisp of a circuit that allows you to drive a blue or white LED from a low voltage.  Normally, if you want to light up a blue or white LED you need to provide it with 3, 3.5 V, like from a 3 V lithium coin cell.  But a 1.5 V battery like a AA cell simply will not work.  But using the Joule Thief, it works like a charm.  Not only does it work with a brand new battery, but it works until the battery is nearly dead-- down to 0.3 V.  That's well below the point where your other toys will tell you the battery is dead, so it can steal every last joule of energy from the battery  (hence the name) .  To learn how to make one, watch the video, which is available in a variety of formats.  __ Evil Mad Scientists Laboratories

Make your own LED Headlamp -  I have submitted here my process for constructing an LED headlamp.  I originally attempted to fit the battery holders for 3 AAA cells along with a tiny PC board for the three LEDs and current limiting resistor all in a tiny altoids tin.  No go.  I ended up buying a 3 cell holder with switch from Mouser electronics, gluing an elbow/ball joint pivot from a desktop pen set I had pieces from to that battery holder, then bolting the pivot to a Walgreens tiny mint tin  (the sugar free ones come in a small oval shaped tin) .  The LEDs  __ Designed by John Evans

Making an Amplified Color Sensor from an LED & an Op Amp -  One of the first lessons that an electronics student learns is that an LED provides light from current flow.  But, did you know that an LED put in backwards provides current flow from light? Yes! It’s true. __ Contact: David Cook

Marx Flasher -  File contains several designs, please scroll to find this circuit.  Here is a strange-looking flasher that uses an unusual form of the Marx high voltage multiplier.  The traditional Marx multiplier uses spark gaps to repetitively charge capacitors from a high voltage supply (in parallel) then to suddenly connect them in  series to generate a much higher voltage, near N times the supply voltage where N is the number of capacitors.  This multiplier uses Lumex gas tube transient suppressors (GT-RLSA3230D) as the spark gap, providing reliable and repeatable triggering at about 250 volts (much lower than the typical spark gap).  The 120 volt line voltage is rectified and doubled to provide enough voltage to trigger the suppressors and to reduce the required number of stages.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Mason_Jar_Solar_Light -  I have modified several commercial solar garden lights over the years.  I switch out the LED, solar panel, battery pack and control circuit.  The result is a much better overall light.  One of my disappointments in using store-bought garden light assemblies is their construction.  They are built so cheaply that over time, water and insects get inside, killing the light operation. . . . Hobby Circuit by David Johnson P.E.-September, 2017

Matrix LED Display -  A minI display using an array de 5x24 LEDs using Microchip PIC  16F628.   __ Designed by Jose Pino

Measure Zener Voltages & Test LEDs -  06/10/10  EDN Design Ideas:  You can use this circuit to measure zener voltages as high as 40V.  To measure a zener diode's breakdown voltage, you need a dc voltage source whose voltage exceeds that of the zener voltage.  In Figure 1, resistor RSER provide as voltage drop between ViN and VZEN.  In any case, ViN should exceed VZEN.  Resistor RSER must provide current, iZEN, that can keep the zener diode in reverse breakdown.  That is, the current must be more than iZEN-iZENMiN and less than iZEN-iZENMAX.  You also need to consider the current that flows through the load.  Otherwise, VZEN will be unregulated and less than the nominal breakdown voltage.  Also, the power that the zener diode dissipates should not exceed the manufacturer's specifications.  Except for the value of iZEN-iZENMiN, all necessary data appears in zener-diode data sheets.   __ Circuit Design by Vladimir Oleynik, Moscow, Russia

MEET BLINKER-blinking LED's -  Our BLiNKER has many applications; fill your party with blinking BLiNKERS.  Mount the BLiNKER on your bicycle so you'll be more visible and have a safer ride.  Mount it on the car dashboard as an alarm flashing light imitator.  Or mount it on your room door (i.  e.  please do not disturb).  Place BLiNKER 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, via two 1.5V batteries, or via one of our battery simulator kits.   __ Contact Kit from Elich Industrial Development, Corp

Message Wand -  The message wand is a good PIC  introduction as it is a simple project yet illustrates many aspects of the PIC  usage.  Used at night, the wand is swung around above the head, and to onlookers spells out a short message in the air using flashing LEDs.  It could also be used with a handle and spun round like a traditional soccer rattle (can you still get those?) though great care must be taken if you do this.  PIC s have been popular with hobbyists for several reasons: The development tools are free, cheap programmers are available, and they come in good old fashioned DiP packages that you can solder to without a microscope!  They are also extremely versatile of course!  The message wand uses a mid-range PIC  – the PIC 16F627.   __ Contact Karen's Microprocessor Projects

Microcontroller drives logarithmic/linear dot/bar 20-LED display -  01/18/07  EDN Design Ideas:  Do-it-yourself analog-to-LM3914 display driver offers user programmability __ Circuit Design by Dhananjay V Gadre and Anurag Chugh, Netaji Subhas Institute of Technology, New Delhi, India

Microscope conversion to LED-Light with two transistor current source -  This instruction shows how to convert a standard microscope with light bulb to LED light.  Only a cheap mobile phone charge can be used as the power supply because of the much lower power consumption of the LED light. __ Designed by Frank Weithöner

Mini Strobe Light using LED -  adjustable for flash rates between40 Hz and166 Hz, based on555 Timer __ Designed by Sunamura Kazuhiro

Miniature Lighthouse Light Simulator -  The circuit I came up with is shown below.  It uses two dual low power op amps.  The first two devices form a classic oscillator circuit whose output is a triangle waveform signal.  That signal is routed to a current regulator circuit, which converts the triangle voltage signal to a triangle current signal through the lighthouse LED.  A third op amp generates pulses timed so they occur at the peak of the triangle waveform.  The result is a LED, which gradually grows brighter, then flashes even brighter before dimming again.  This should produce a light, which simulates a rotating lighthouse light . . . Circuit Solution by Dave Johnson P.E.-May, 2006

Miniature Surface-Mount LED Ring Light -  Ring lights provide shadowless all-around lighting that is particularly useful for close-up work such as macro-photography and circuit-board inspection with a magnifying glass.  This project also includes instructions on soldering surface-mount electronic components and machining a circuit board into a ring (round/circular/donut) shape.   __ Contact David Cook

Mini-Beacon miniature programmable LED Flasher that is based around a PIC12F629 microcontroller -  This project, called "Mini-Beacon", is a miniature programmable LED Flasher that is based around the PIC  microcontroller.   This project grew out of an idea and recommendation posted on RunRyder.com.   The Mini-Beacon basically simulates the light emitted from a rotating light beacon such as those used in older police cars and fire engines.   As seen from the observer's perspective, __ DIY RC

Model Airplane Wing Tip Flasher -  The circuit below is designed to flash two white LEDs mounted at the wing tips of a model airplane.  The flasher unit is powered by a 4.5v supply made of three AA or AAA 1.5v alkaline battery cells.  The average current is about 2ma so a set of batteries . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2009

Model Lighthouse -  This project was designed for a model lighthouse to flash a lamp or LED in a simple sequence: two flashes of 2s with a short gap of 1s, followed by a longer gap of 5s before repeating the sequence.  A 4017 counter is used to produce the flash sequence and this project includes information on how to adapt it to give a different flash sequence __ Designed by John Hewes

Model Train Lighthouse Flasher Revisited -  HO train sets often have authentic looking scale model homes and buildings.    A while back someone asked me to design a flashing LED light, which he could mount inside a model lighthouse and have it operate so it would appear to rotate and flash.    I designed a working circuit but I was never pleased with the results.    i’m still not 100% pleased but the revised circuit below seems to operate a bit better than the older circuit.  … [Hobby Circuit designed by Dave Johnson P.  E.  , May 2012] . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2012

Modified 4 D Cell LED Lantern -  While shopping at a sporting goods store one day, I spotted a compact LED lantern.  It looked like the kind of lantern I could modify. The lantern LEDs were grouped into three sections of 7 LEDs each, oriented into 120 degree angles.  The LEDs were standard T 1-3/4 epoxy types.  The lantern had a three mode switch which selected between off, full power and half power modes.  At the half power mode, only half of the 21 LEDs were illuminated.  At full power all LEDs were illuminated. . . . Circuit by David Johnson P.E.-September, 2017

Modified Colman Lantern3 -  While shopping at a sporting goods store one day, I spotted a compact LED lantern.  It looked like the kind of lantern I could modify. The lantern LEDs were grouped into three sections of 7 LEDs each, oriented into 120 degree angles.  The LEDs were standard T 1-3/4 epoxy types.  The lantern had a three mode switch which selected between off, full power and half power modes.  At the half power mode, only half of the 21 LEDs were illuminated.  At full power all LEDs were illuminated. . . . Circuit by David Johnson P.E.-September, 2017

Modified LED Night Light -  I bought some night lights a few months ago from Walmart here in Denver.  The devices were made by Elumina Lighting Technologies inc. (www.  eluminalighting.  com) , their model LED-6200A.  I think I paid about $15 for a pack of three lights.  I wanted a light . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2007

Monolithic Converter Drives High Power LEDs -  DN376 Design Notes__ Linear Technology/Analog Devices

Motion Sensing LED -  Hack your box of chocolates with arduino iDE and ATtiny13. __ Contact Jameco Electronics

Moving Message Display -  it's easy to build, easy to program, easy on the pocket and easy on the eye.__ SiliconChip

Moving Message Display On LCD -  Moving-message displays are ideal to get your message (advertisements, greetings, etc) across in an eye-catching way.  You can make an LCD show a brief moving message by interfacing it to a__ Electronics Projects for You

MSP430 Interface to TPS60250 via I2C Master Software -  LED lighting designers are challenged with meeting their efficiency and reliability goals faster in advanced LED lighting designs.  LED lighting customers seeking the latest in innovative and affordable LED lighting solutions can benefit from Ti's broad product portfolio of LED drivers, AC/DC, DC/DC, power management devices, wireless and wired interface control and embedded processors.  LED designers have the option of not only controlling the power stage, but regulating LED currents as well, eliminating the need for multiple components and reducing system cost.   __ Designed by Texas Instruments App Notes, 1-May-08

Multi-Colour LED Christmas Tree -  A low-cost microcontroller chip that produces multiple colours and multiple patterns.__ SiliconChip

Multidisplay LED Controller -  LTC3205__ Linear Technology/Analog Devices

Multiple Applications Of High-Power Leds -  Nowadays, high-power light-emitting diodes (LEDs) LXHLMW1C are available in the market.  These white LEDs contain indium-gallium-nitrogen (inGaN).  The LEDs’ emitting capacity is 20 candela (Cd).  We can use these LEDs for__ Electronics Projects for You

Multiple LED flasher -  This circuit will flash a string of LED's, typically 16, with direct connection to the mains and with a period adjustable between 1 and 4 seconds depending on the setting of the 22K/1W pot.  Operation at 110V should also be possible but has not been tested.  __ 

Multipurpose White-LED Light -  Standard fluorescent lamps and their smaller versions called compact fluorescent lamps (CFLs) radiate light in all directions (360°) and tend to increase the room temperature.  In emergency lights using these lamps, __ Electronics Projects for You

Multi-Segment LED Display -  Lite-On LTM-Y2K19JF-03 is a surprisingly good LED display with alphanumeric, numeric, and icon LEDs.  The LED module includes all driver circuitry -- no additional transistors or resistors are necessary.  The article also describes how to create and edit a 14-segment alphanumeric LED font using Excel.   __ Contact David Cook

Negative 0.5 Volt Supply -  This simple circuit consists of two LEDs and a photo diode.  It generates a negative voltage with a current level of a couple milliamps.  It is ideal for supplying a negative rail to low power “rail to rail” op amp circuits, which need to have a true zero volts output.  Note:  This circuit is not particularly efficient . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006

Night Light from White LED -  As many of you know, I have a pet peeve with poorly made LED night lights.  Often, the light from the LED quickly fades, so within months, the light is useless.  I have posted several versions of modified night lights using higher quality components . . . Circuit by David A. Johnson P.E.-November, 2008

Night_Light_with_20_LED -  After 3 years of continuous 24/7 operation I noticed that the 20 LED array I was using as a night light next to my back door was fading.  Some of the LEDs were much dimmer than others.  I figured that over time, the internal heat dissipated from the LED chip was causing the LED light intensity to fade.  I decided it was time to replace the light. . . . Hobby Circuit by David Johnson P.E.-July, 2017

Nine-Volt Battery Voltage Monitor -  This circuit turns on a LED whenever the voltage of a standard 9v battery connected to the circuit drops below 7.2 volts.  It uses a LTC1440 comparator, which also contains a 1.18v reference diode.  In standby mode, the circuit draws only 4uA . . . Circuit by David Johnson P.E.-July, 2006

Not 1 But 2 White LED Torches to build -  These LED torches produce a beautiful even spread of white light which is quite different from that of conventional torches using Krypton bulbs.__ SiliconChip

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LEDs:   #'s - B     C - G      H - L       M - P       Q - T     U - Z 

 


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