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

Last Updated: June 02, 2021 01:45 PM

Circuits Designed by Dave Johnson, P.E. :

 Does Power Line have 120 VAC or 240 VAC?Two LEDs indicate if a power line has 120vac or 240vac voltage on it. . . Circuit by Dave Johnson P.E.-July, 2006

 Drive a LED with an Intensity Ramping ModeThe circuit below was designed to drive a LED with an intensity ramping mode.  Two 555 timers generate two different triangle waveforms.  The upper device generates a 10KHz signal while the lower unit produces a 1Hz signal.  The two signals are fed to a . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2007

 Either Indicates 120 VAC or 240 VAC  - Two LEDs indicate if a power line has 120vac or 240vac voltage on it. . . Circuit by David A. Johnson P.E.-July, 2006


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

Drive White LEDs -  11/23/00 EDN-Design Ideas Newly available white LEDs are replacing CCFLs  (cold-cathode fluorescent lamps] in handheld applications using a back-lit LCD.  These applications include PDAs  (personal digital assistants], digital cameras, and cellular telephones,  Design by Eddy Wells, Texas Instruments

Driver Lights Architectural & Interior LEDs -  08/11/11 EDN-Design Ideas Hold the current constant and within tolerance.  LEDs are more efficient than incandescent lights and can last 100 times longer, but they require specialized electronic-drive circuits to avoid overstress conditions.  The main operating parameter is relatively simple: Keep the current through the LEDs constant and under the specified maximum.   Design by Steve Sheard, On Semiconductor, Tempe, AZ

Driver thermally compensates LED -  09/02/99 EDN-Design Ideas Optical power of popular types of LEDs decreases with temperature.  Optical-power measurements into a typical multimode fiber at 62.5/125 ?m for a GCA 1A194 LED indicate a temperature coefficient of approximately -0.4%/°C.  In bipolar analog drivers for short- and medium-distance fiber links Design by Andrzej Wolczko, University of Mining and Metallurgy, Krakow, Poland

Driving a Bi-Coloured LED -  Some 3-leaded LEDs produce red and green.  This circuit alternately flashes a red/green bi-coloured LED__ 555-Timer

Driving Dot LED -  A basic circuit of the 89C2051 shown here can be made easily using point-to-point soldering with a universal PCB.  Use an ordinary 20-pin socket, do not use a circle-pin socket.  D1 is a small dot LED.  U2 can be either 7805 or 78L05.  U3 is optional for correcting any polarity DC adapter.  Without the 2051 chip __ Designed by Wichit Sirichote

Driving LED display matrix from a PIC micro -  Driving a 64 LED dot matrix LED display is quite simple and just requires ONE TRICK!    Here you can find out how to drive an led dot matrix with 64 LEDs  (8 rows by 8 columns8x8 display) or less e.g.35 LEDs  (7 rows by 5 columns5x7 dot matrix) .  However the principle remains the same for larger displaysyou may need more processing power and driver circuitry though. __ Designed by John Main

Driving White LEDs -  The 555 is capable of sinking and sourcing up to 200mA, but it gets very hot when doing this on a 12v supply.  The following circuit shows the maximum number of white LEDs that can be realistically driven from a 555 and we have limited the total current to about 130mA as each LED is designed to pass about 17mA to 22mA maximum.  A white LED drops a characteristic 3.2v to 3.6v and this means only 3 LEDs can be placed in series.  __ 555-Timer

Dual Full Function White LED Step-Up Converter with Built-In Schottky Diodes -  LT3466__ Linear Technology/Analog Devices

Dual LED dice -  Our dual DICERD6 has many applications; Play your game with  DICER.  A backgammon lover's dream.  Great for craps.  No more dice fixing! Remember, casino games are for adults, only.  Use your ESP to guess the next "roll"  Use the dual LED-dice kit anywhere you’d like to draw an audience and a smile.   __ Contact: Kit from Elich Industrial Development, Corp

Dual LED Flasher -  Some useful circuits using the LM555 IC.  Scroll to find the Dual Led Flasher circuit __ Designed by Jose Pino

Dual White LED Driver Features Integrated Switches & Schottky Diodes in 3mm × 3mm Dfn Package -  DN1010 Design Notes__ Linear Technology/Analog Devices

Dynamic Display using LED Strip -  Surface-mount device  (SMD) LEDs are becoming popular because of their low power consumption and high brightness.  These LEDs are readily available in the market in many colours both as single LEDs...__ Electronics Projects for You

Dynamo-Powered LED Headlight & Tail Light for your Bicycle -  Three classes of LED light systems are presented: Basic, Medium Power and High Power, a tip

Economical drives white LEDs -  11/23/00 EDN-Design Ideas Newly available white LEDs are replacing CCFLs  (cold-cathode fluorescent lamps] in handheld applications using a back-lit LCD.  These applications include PDAs  (personal digital assistants], digital cameras, and cellular telephones,  Design by Eddy Wells, Texas Instruments

Efficient LED Blinking for Embedded Systems -  Smart hardware design can simplify the embedded software and make it more reliable.  Designers use blinking LED signals to indicate different status and for inbuilt testability.  Making an LED array blink...__ Electronics Projects for You

Efficient LED Power Supply Has Battery Backup -  04/08/10 EDN-Design Ideas Power three to six LEDs from an ac- or dc-power source and charge a backup battery.   Design by Zhihong Yu, Juno Lighting Group, Des Plaines, I - L

Efficiently Switches Bipolar LED -  11/22/01  EDN-Design Ideas The circuit in Figure 1 represents one method to switch a bipolar, two-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 substantiallythan t Design by Spehro Pefhany, Trexon Inc, Toronto, ON, Canada

Eight LEDs Make a 100-Division Voltmeter -  09/22/11  EDN-Design Ideas Use a counter IC to drive two sets of four LEDs.  The circuit in this Design Idea makes a voltmeter that reads to 0.99V.  The idea uses a counter IC to drive two sets of four LEDs    (Figure 1) .  Each of these two sets represents a BCD    (binary-coded-decimal) value.  With all of the LEDs off, the voltmeter reads 0V.  With all of the LEDs on, the reading is 0.99V.  Op amp IC1A generates a predictable voltage ramp. Design by Raju Baddi, Tata Institute of Fundamental Research, Pune University, Maharashtra, India

Eight LEDs Random Flasher -  This project uses a 4026 counter and display driver IC to flash eight LEDs in an apparently random manner.  It can be used to create a display of your choice.   __ Designed by John Hewes

Either Indicates 120 VAC or 240 VAC  -  Two LEDs indicate if a power line has 120vac or 240vac voltage on it. . . Circuit by David A. Johnson P.E.-July, 2006

Electronic Christmas Tree -  Schematic + Info + pictures __ Designed by Lennie Zink

Electronic Dice -  A LED dice, bright, unbiased, and spectacular.  The display uses 7 LEDs to simulate the faces of a real dice.   __ Designed by Projects & Ideas from Nutchip.com

Electronically Tinge White-Light Source -  EDN-Design Ideas 11/04/10    A tricolor LED lets you produce different shades of white  Design by Marián Štofka, Slovak University of Technology, Bratislava, Slovakia

Emergency Lamp & Turning Indicator -  White LEDs are replacing the conventional incandescent and fluorescent bulbs due to their high power efficiency and low operating voltage.  These can be utilised optimally for emergency lamp and vehicle turning...__ Electronics Projects for You

Emergency Light -  A simple circuit that activates a light when the power is out.  A version with a lightbulb and another with white LED light included.   __ Designed by Jose Pino

Emergency Light with Charger -  White LEDs are replacing the conventional incandescent and fluorescent bulbs due to their high power efficiency and low operating voltage.  These can be utilised optimally for emergency lamp and vehicle turning...__ Electronics Projects for You

End of Train Flasher -  Schematic + Info + pictures __ Designed by Lennie Zink

Enhanced Security Bike LED Light -  Adds movement detection and visual effects to enhance visibility to motorists.3 LEDs flash simultanuously in normal mode.  Various light effects when a small movement or direction change is detected.  All 3 LEDs light up for 1,5 sec when braking occurs. __ Designed by Michel Bavin

Expandable 16 Stage LED Sequencer -  The circuit below uses a hex Schmitt Trigger inverter  (74HC14) and two 8 bit Serial-In/Parallel-Out shift registers  (74HCT164 or 74HC164) to sequence 16 LEDs.  The circuit can be expanded to greater lengths by cascading additional shift registers and connecting the 8th output  (pin 13) to the data input  (pin 1) of the succeeding stage.  A Schmitt trigger oscillator  (74HC14 pin 1 and 2) produces the clock signal for the shift registers, the rate being approximately 1/RC.  Two additional Schmitt Trigger stages are used to reset and load the registers when power is turned on.  Timing is not critical,  __ Designed by Bill Bowden

Experiments with an Encoder  -  Encoders are beleieved to be mysterious.  Follow our instructions to learn all its secrets.  You will understand why it is increasingly adopted in so many industrial products, from machines, to positioners, and even microwave ovens and car stereos.   __ Designed by Projects & Ideas from Nutchip.com

Extend white LEDs' operating life -  01/18/07  EDN-Design Ideas PWM-controller loop stabilizes light output Design by Bjoy Santos, Intersil Corp, Milpitas, CA

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