LED Light Emitting Diode Electronic Circuits, page 11c

LED (Light Emitting Diodes) Circuits Page 11c
LED: # A B C D - E F - H I - K L M - O P- R S T U - V W -Z
Last Updated on: Wednesday, November 29, 2017 05:40 AM

Circuits Designed by Dave Johnson, P.E. :

Simple WHITE LED NIGHT LIGHT
This 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. The LEDs are mounted in a box and are angled slightly to bounce the light off of a nearby wall. The light should last about 10 years. The circuit draws less than one half of one watt of power and can therefore run continuously. In spite of the low power, the LEDs provide sufficient illumination for most night light applications. Circuit component values for both 120vac and 240vac are shown.

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 is powered by any 3v source. I suggest two AA cells but a single 3v lithium coin type cell will also work. With fresh AA cells, the light should flash for about two weeks. The light flash is very intense and is perfect for any attention getting night time application.....

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

Sky Writer - We have seen many projects using a set of LEDs to produce words "in the air," but none have the feature of an inertia switch to provide registration. One of the biggest problems with waving a display to produce writing .....(electronic schematic added 05/08)

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. [G. Forrest Cook]

Special Lighting - experiments with white LEDs (added 4/02)

SPI Interface Big 7-Seg LED - Easy build and use, the general purpose Big LED with SPI serial interfacing. Expandable for multiple digits but still uses only three wires for receiving data from any uC boards… [Wichit Sirichote, kswichit@kmitl.ac.th]

Stealth-mode LED controls itself - 5/25/06 EDN Design Ideas.....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 in two directions. Certain bright, efficient LEDs, such as Hewlett-Packard’s (www.hp.com) HLMP-EG30-NR000, a red emitter molded in clear encapsulation, also exhibit significant.....PDF has several circuits, you will need to scroll to find this one..... [Design Idea by Howard Myers, Greensboro, NC]

Step-Down Conversion Concept for a PWM-Mode Boost Converter - TI Application Note (added 2/06)

Strange LED Sequencer - This bizzare but simple PWM circuit fades from LED to LED. This deceptively simple sequencer actually pulse width modulates the LEDs as it fades from one LED to the next. Bulbs will last much longer when driven in this gentle manner; add FETs or transistors to the outputs if you wish to drive bulbs. You can reconfigure the capacitors.....(added 2/05) [Circuit by Stepan Novotill]

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 is powered by any 3v source. I suggest two AA cells but a single 3v lithium coin type cell will also work. With fresh AA cells, the light should flash for about two weeks. The light flash is very intense and is perfect for any attention getting night time application..... [Designed by David A. Johnson]

Super Simple Flasher - Scroll down to find this circuits. 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 …..(added 07/07/07)

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.… EDN is migrating links. This link is not verified. Google the "title" EDN for new link.

Synchronous Buck/Boost High Power White LED Driver - Linear Technology LT3453.....[App Note]

Synchronous Step-Up DC/DC Converter for White LED Application - National Semiconductor Application Note LM3500 February 05.....[App Note]

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