LED Light Emitting Diode Electronic Circuits -

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. :

AC Line Powered LED FlasherSome of the latest LEDs are amazing. They can produce a surprising amount of light with very little current. In the light flasher application shown below I take advantage of a nice surface mounted LED from King Bright. This flasher circuit draws only about 3ua of average current from the AC power line to flash this green LED. This flasher might be used as a power indicator light . . . Hobby Circuit designed by David Johnson P.E.-December, 2008

AC Line Powered LED Pilot LightThis simple circuit can be used to light a LED indicator lamp, powered from the 120vac line. I have included component values for 240vac lines as well . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

AC Line Powered LED StringsThis shows 4 different ways to string white LEDs that are powered by a 120vac or 240vac power line. This hobby circuit was designed by Ken Schultz.. . . Circuit by David Johnson P.E.-December, 2004

AC Power Loss AlarmI’ve been having a problem with my instant hot water system lately. This system circulates electrically heated water throughout my house using a small pump. The pump is wired into a ground fault interrupter (GFI) module. Every now and then, the GFI trips, leaving me without hot water. . . Circuit by David A. Johnson P.E.-March, 2009

Active AC Power Line IndicatorThe circuit below is designed to detect when a power cable is active (hot) . When the flat sensor end of the device is held near an active AC line, the bright green LED on the top of the housing will glow. It is powered by a 3v CR2032 lithium coin cell. I. . . Circuit by Dave Johnson P.E.-May, 2005

Advertising Badge #1 with Flashing LEDI have seen numerous flashing light badges at trade shows and conventions. They are often handed out as gifts to promote some business. The devices often use inefficient circuits, which cause the battery power source to be quickly depleted. . . Circuit by David A. Johnson P.E.-March, 2002

Advertising Badge #2 with Flashing LEDThis circuit uses a CD4013 dual D Flip/Flop IC. A single lithium battery will provide months of continuous LED flashing. It also has a tiny push-button switch to turn on and off the light flashing. . . Circuit by Dave Johnson P.E.-March, 2002

AIR Transparency Monitor, Xenon Flash TransmitterThis is the matching transmitter for the above receiver. The transmitter launches powerful 1000-watt light pulses that last about 20 microseconds. . . Circuit by David A. Johnson P.E.-June, 2000

Auxiliary 12v Automotive Style LED Light Makes Table LampThis circuit provides about one watt of non-isolated DC power for an automotive type 12v LED array lamp in addition to a standard incandescent table lamp . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

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

Add switch-and-LED I/O to DSPs serial port - 05/07/98 EDN-Design Ideas - (file contains multiple circuits scroll to find this one.) When you debug an embedded DSP design, it's handy to have a bank of switches and LEDs to simulate inputs or to display intermediate results. You can attach 16 switches an Design by Stan Sasaki, Twenty-First Designs, Lake Oswego, OR

Adjust Power-Efficient LED Switch to Any Light Intensity - EDN-Design Ideas 06/20/12 Drawing only microamps (other than load current) , this circuit switches in accordance with ambient light levels. Design by Raju Baddi, Tata Institute of Fundamental Research, Pune, India

Advanced LED temperature indicator - This project illustrates the use of a V/F converter in monitoring temperature in degrees Fahrenheit (0F) . The block diagram of the temperature indicator is shown in Figure 1-1. __

Advertising Badge #1 with Flashing LED - I have seen numerous flashing light badges at trade shows and conventions. They are often handed out as gifts to promote some business. The devices often use inefficient circuits, which cause the battery power source to be quickly depleted. . . Circuit by David A. Johnson P.E.-March, 2002

Advertising Badge #2 with Flashing LED - This circuit uses a CD4013 dual D Flip/Flop IC. A single lithium battery will provide months of continuous LED flashing. It also has a tiny push-button switch to turn on and off the light flashing. . . Circuit by Dave Johnson P.E.-March, 2002

AIR display - A Noisemaker without noise. A simple rotating display. Just spin and enjoy. While the "Air display" is rotating, it writes the message on the air. Because the "persistence of the vision", you will be able to read the message. Circuit, see JP6293E. gif. __ Designed by Jose Pino

AIR Transparency Monitor, Xenon Flash Transmitter - This is the matching transmitter for the above receiver. The transmitter launches powerful 1000-watt light pulses that last about 20 microseconds. . . Circuit by David A. Johnson P.E.-June, 2000

Alphanumeric LED Display Project - A phenomenal 256-diode ROM acts as a character generator for a two-digit hexadecimal display. __ Contact: David Cook

Alternating LED flasher uses minimal parts - 11/20/97 EDN-Design Ideas A pair of alternating flashing LEDs makes an excellent visual alarm, this alternating LED flasher is based on one LED with built-in flashing function and two transistors driving or normal LED. Design by Dennis Eichenberg, Parma Heights, OH

Alternating LED blinker uses four 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

Alternating LEDs Flasher - 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

An Automotive Halogen Headlamp Power Supply - This circuit example demonstrates using a SEPIC-based automotive halogen headlight power supply that improves bulb reliability while also ensuring optimum illumination. The design maintains 12V at headlight voltage over a 9V to 15V input voltage range. It works well up to 1Ω interconnection resistance. The Virtual Remote Sense __ Linear Technology/Analog Devices App Note, Jul 7th 2010

An Efficient & Low Cost Alternative to LEDs for Backlighting Handheld Computer Displays - DN1004 Design Notes__ Linear Technology/Analog Devices

An improved offline driver lights an LED string - 01/25/13 EDN-Design Ideas A constant current is better than a constant voltage for driving LEDs. In this proposed circuit, a common constant-voltage regulator is changed into a constant-current source for LEDs. In addition, a startup current limiter is used to suppress large current surges, and a voltage chopper is employed for a wide ac input of 96 to 260 VRMS. Design by Yan-Niu Ren, Southwest Petroleum University, Chengdu, China

An LED Flasher with a SlowRise & Fall Time - Here is a Simple Circuit to give a Flashing LED, With a "Rising and Falling" Brightness. It Uses the Sawtooth waveform from pins 2 and 6 to create the rise and fall. The Resistor and LED on Pin 3 are Optional. The 10K Potentiometer give a reasonable range of Speed. __ Designed by G.L. Chemelec

An LED's Intrinsic Capacitance Works In a 650-Mv LRC - EDN-Design Ideas -- 09/08/11 The LED and a discrete inductor form an LC tank circuit. Design by Sajjad Haidar, University of British Columbia, Vancouver, BC, Canada

An Up / Down Digital Counter with 7 Segment LED Displays - REVISED Really as Simple as you can get and has 4 Displays __ Designed by G.L. Chemelec

<<< >>>

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