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

Last Updated: December 07, 2017 02:05 PM

Circuits Designed by Dave Johnson, P.E. :

 Simple Circuit for White LED Night LightThis simple circuit is designed to plug into a standard AC electrical outlet.  It uses four super bright white light emitting diodes (LED) in conjunction with a capacitor coupled full wave rectifier circuit. . . Circuit by David A. Johnson P.E.-July, 2003

 Simple Circuit Negative Supply CircuitThis 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 Johnson P.E.-July, 2006

Solar Fireflies In Jar Light -  When I was a kid, growing up in Illinois, I remember catching fireflies and putting them into a jar.  I loved watching them flashing away at night.  Later, I would let them out to live another day. . . . Circuit by David Johnson P.E.-September, 2017

Solar Mason Jar 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. . . . Circuit by David Johnson P.E.-September, 2017

Solar Powered Lighthouse -  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. . . . Circuit by David Johnson P.E.-September, 2017

Solar-Powered_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 14, 2017
Solar-Powered_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 14, 2017

Solar Powered Flood Light using NiMH -CellsThere are many solar powered garden lights available.  Most of the devices offered at the home improvement stores have very poor performance.  Their batteries are too small, the light launched is weak and the solar panels are undersized.  None of the devices I have tested would operate through a typical night. . . Circuit by Dave Johnson P.E.-December, 2013

 Solar Powered Infrared 1W Security Camera IlluminatorMany security cameras are equipped with an array of infrared LEDs to illuminate an area in front of the camera with invisible light for night time surveillance.    However, there are times when a remote area, well away from the camera, needs additional infrared light.    The circuit below uses a modified solar powered path light to bathe a fairly large area with 850nm infrared light. . . Circuit by Dave Johnson P.E.-June, 2014

 Solid State Relay that is BidirectionalThe circuit below can switch up to 4 amps of current with a peak voltage up to 20v.  It is fully isolated using two inexpensive red LEDs.  One LED forms a red light source, which illuminates a second red LED.  The circuit takes advantage of the 1.5v . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2009

 Sound Triggered Night LightA while back, I received a schematic from a guy by the name of Karl.  He described a situation he and his wife found themselves in aboard a cruise ship in the Caribbean.  They were staying in a room toward the inside of the ship, which did not have any port holes, windows or a balcony. . . Circuit by David Johnson P.E.-August, 2013

 Super Bright 3v Powered LED FlasherI have posted several kinds of LED flashers over the years.   This is yet one more flasher, designed to flash any high power LED of any color.  It hits the LED with a 25ms 250ma pulse once every 2 seconds.   This works out to an average current about 3ma.  It. . . Circuit by Dave Johnson P.E.-April, 2009


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

Single & Two Cell White LED Drivers Without Inductors -  The operating voltage of white LEDs coupled with my emotional need for low cost for a given function, motivates me to make LED drivers suitable for battery operated lanterns that can run from a small number of cells.  White and Ultraviolet LEDs __ Designed by Dick Cappels

Single Cell Flashes White LED -  12/11/03 EDN-Design Ideas Many portable appliances and other products that must operate from a single cell are restricted to working at very low voltages.  It is thus difficult to drive white LEDs that typically have a forward voltage of 3 to 5V.  The ability __ Circuit Design by Anthony Smith, Scitech, Biddenham, Bedfordshire, UK

Single cell LED flasher with two-year battery life (LM3909 replacement) -  This circuit is a discrete replacement for the LM3909 LED flasher IC, with considerably lower current consumption, of less than 50µA as opposed to a typical 0.55mA quoted in the LM3909 datasheet. A single alkaline AA cell can be expected to last two to threeor moreyears, as compared with a few months for the LM3909. It was designed as a replacement for the LM3909 unit installed in the packaging of Pink Floyd's "Pulse" album in order to decrease the frequency with which the casing would have to be pulled apart to replace the AA cell, in which it was very successful. It is easily constructed on a piece of Veroboard the same size as the original PCB, using the original LED and battery holder __ Designed by Pigeon
Single cell LED flashlight -  A driver circuit for high efficiency white LEDs that runs on a single rechargeable or alkaline cell.   __ Designed by Manfred Mornhinweg

Single cell lights any LED -  07/05/01  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 i __ Circuit Design by Al Dutcher, Al Labs, West Deptford, NJ

Single Cell TPS61041 LED Driver -  Texas Instruments provides a broad portfolio of high-performance products for your LED design needs.  From RF and power management  (including AC/DC, Power Factor Correction, DC/DC and linear power conversion) to DSPs and ultra-low-power MCUs, TI has products to differentiate your design.  And, TI's local support and applications expertise can help you get to market faster.   __ Designed by Texas Instruments App Notes, 9-Jun-03

Single Cell TPS61041 LED Driver Slva136.Htm, 1 Kb -  TI App Note 

Single FET Controls 2nd LED Array in Switchmode LED Backlight -  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.  __ Maxim Integrated

Single FET controls LED array -  04/12/01 EDN-Design Ideas White-LED backlights are gaining acceptance because they offer higher reliability and simpler drive circuitry than backlights based on CCFL   (cold-cathode-fluorescent-lamp] and EL   (electroluminescent] technology.  As a result, white-LED backlights are increasingly common in PDAs   (personal digital assistants], cell phones, digital cameras, and other portable devices.  A design __ Circuit Design by Len Sherman, Maxim Integrated Products, Sunnyvale, CA

Single LED dice kit -  Our DICER-S6 has many applications; Play your game with  DICER.  Use the single LED-dice kit anywhere you’d like to draw an audience and a smile.  No more dice fixing! Use your ESP to guess the next "roll"  The unique small design will allow you to mount kit almost anywhere.  Operates 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

Single LED flasher -  Flashing a LED should not require a complex circuit.  A reverse biased transistor does the job in a nice way.  Circuit "a" flashes the LED twice a second: changing the capacitor and/or the resistor will change the frequency, also the supply voltage

Single LED Indicates Two Power States -  12/05/96 EDN-Design Ideas  Uses a single bicolor LED to indicate both power-on and blown-fuse conditions.    __ Circuit Design by Jim Hagerman, Hagerman Technology, San Diego, CA

Single-Cell White-LED Driver Uses Improvised Transformer -  02/01/07  EDN-Design Ideas Minimal component-count circuit boosts a single cell's voltage to light an LED. __ Circuit Design by Jim Grant

Single-port pin drives dual LED -  10/13/05 EDN-Design Ideas Single-line LED driving can be versatile __ Circuit Design by Tom Gay, Dornstadt, Germany

Smart Mixture Display for Your Car -  A 10-LED display indicates the fuel mixture, while a small buzzer sounds if the mixtures go dangerously lean.__ SiliconChip

Solar Charged LED Utility Light -  Tired of always spending money on flashlight batteries only to have them fail just when you need them? Try this simple circuit out.  It would make an excellent science fair project.  The white LEDs are quite bright, they provide enough light to illuminate a small room at night.  The LEDs produce a nicely focused beam.  You can read by the light of this device.   __ Designed by G. Forrest Cook

Solar Fireflies In Jar Light -  When I was a kid, growing up in Illinois, I remember catching fireflies and putting them into a jar.  I loved watching them flashing away at night.  Later, I would let them out to live another day. . . . Circuit by David Johnson P.E.-September, 2017

Solar Mason Jar 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. . . . Circuit by David Johnson P.E.-September, 2017

Solar Powered Flood Light using NiMH
Cells
-  There are many solar powered garden lights available.  Most of the devices offered at the home improvement stores have very poor performance.  Their batteries are too small, the light launched is weak and the solar panels are undersized.  None of the devices I have tested would operate through a typical night. . . Circuit by Dave Johnson P.E.-December, 2013

Solar Powered Infrared 1W Security Camera Illuminator -  Many security cameras are equipped with an array of infrared LEDs to illuminate an area in front of the camera with invisible light for night time surveillance.    However, there are times when a remote area, well away from the camera, needs additional infrared light.    The circuit below uses a modified solar powered path light to bathe a fairly large area with 850nm infrared light. . . Circuit by Dave Johnson P.E.-June, 2014

Solar Powered LED Lamp -  Here is the simple solution to make an automatic solar powered led lamp.  It automatically switches on two high power White LEDs in the evening and stays on for 6 hours using a 6 volt 4.5 Ah rechargeable battery.  A 12 volt solar panel is used to charge the battery during day time.  The battery is connected to the input line __ Designed by D Mohankumar

Solar-Powered_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 14, 2017

Solar Powered Lighthouse -  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. . . . Circuit by David Johnson P.E.-September, 2017

Solar Powered Night Light -  The goal of this project was to produce a self contained reading lamp that could be used by students in developing countries for reading at night.  The circuit can be used for a wide variety of lighting applications __ Designed by G. Forrest Cook

Solar Powered Reading Lamp -  The goal of this project was to produce a self contained reading lamp that could be used by students in developing countries for reading at night.  The circuit can be used for a wide variety of lighting applications __ Designed by G. Forrest Cook

Solid State Relay that is Bidirectional -  The circuit below can switch up to 4 amps of current with a peak voltage up to 20v.  It is fully isolated using two inexpensive red LEDs.  One LED forms a red light source, which illuminates a second red LED.  The circuit takes advantage of the 1.5v . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2009

Sound Triggered Night Light -  A while back, I received a schematic from a guy by the name of Karl.  He described a situation he and his wife found themselves in aboard a cruise ship in the Caribbean.  They were staying in a room toward the inside of the ship, which did not have any port holes, windows or a balcony. . . Circuit by David Johnson P.E.-August, 2013

Special Lighting  -  experiments with white LEDs

Speed Adjustable 4 Sequence LEDs -  Our SEQUENCERS4 has many applications; simply power the board and light 4 LEDs start to "move, " left to right again and again in sequence! This automatic sequence of blinking lights  (LED) can be controlled directly from a front mounted multi-turns trimmer  (pot.) and will draw attention and fun! The unique small design will allow you to mount it almost anywhere.  Operate it with 6V, 9V battery, 12V car battery, four 1.5V batteries, or via one of our battery simulator kits __ Contact: Kit from Elich Industrial Development, Corp

SPI Interface Big 7-Seg LED -  Big display for general purpose usage, the interfacing is SPI serial interface, requires only 3-wires.  Multiple digit can easily be made.  DXF files single side PCB.   __ Designed by Wichit Sirichote

Stealth-mode LED controls itself -  05/25/06  EDN-Design Ideas High-efficiency LED doubles as a light detector- Since the LED’s invention more than 30 years ago, its emission efficiency has steadily increased, and,although it may surprise you, the increased conversion efficiency works i __ Circuit Design by Howard Myers, Greensboro, NC

Step-Down Conversion Concept for a PWM-Mode Boost Converter -  TI App Note 

Super Bright 3v Powered LED Flasher -  I have posted several kinds of LED flashers over the years.   This is yet one more flasher, designed to flash any high power LED of any color.  It hits the LED with a 25ms 250ma pulse once every 2 seconds.   This works out to an average current about 3ma.  It. . . Circuit by Dave Johnson P.E.-April, 2009

Super Simple Circuit Flasher -  File contains several designs, please scroll to find this circuit.  Here is a simple flasher circuit that uses no resistors! However, it relies on leakage in the base of the PNP germanium transistor and only some will work; be prepared to try a few.  If you add a 100k resistor from the base to the collector of the PNP, the circuit will work with most germanium transistors and will work down to 1 VDC! The NPN should be a silicon type.  The 100 uF may be replaced with a 22uF in series with a 5k resistor and it would be a good idea to add 39 ohms in series with the base of the NPN  (but then the circuit starts to lose its charming simplicity) .   __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Switched Capacitors Provide Efficient & Functional White-LED Drive -  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, 6-Mar-03

Switched Caps Provide Efficient & Functional White LED Drive (Rev. B) -  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, 30-Apr-13

Switching regulator efficiently controls white-LED current -  04/27/06 EDN-Design Ideas Circuit has 93% efficiency and beats 64% efficiency of series resistor approach __ Circuit Design by Clayton Grantham

Synchronous Buck/Boost High Power White LED Driver -  LT3453__ Linear Technology/Analog Devices

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


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