Laser-Diode Driver Stabilizes Sensitivity Parameters  -  11/05/98 EDN Design Idea   (File has many circuits, scroll to this one) The conventional advantages of lasers—coherence, monochromaticity, and extreme compactness—make laser diodes popular in most of their potential applications. Biomedical diagnostics and. . .  [by Anil Kumar Maini and Nita Sen, Defence Science Centre, Delhi, India]

Latching relay driver  -  Schematic only, no circuit description. . .  [Designer's name not given]

Latching, transistorised  -  . . .  [Page's Author: Richard Torrens]

LED Array powered by 24 VAC  -  24vac is a popular voltage. It is often used in low voltage lighting systems and industrial controls. It is much less dangerous than 120vac/240vac line voltages. This hobby circuit below is one method to efficiently power a cluster of 7 white LEDs from 24vac.  . . . [Hobby Circuit designed by Dave Johnson P.E.

LED Camping Lantern with Dimmer  -  A while back I received an email from a Discover Circuits visitor who wanted to build his own LED camping lantern. He wanted to use a single bright LED powered by 3 large alkaline D cells. He also wanted to be able to dim the light intensity down to a low night light level, to extend the battery life. The circuit below performs this task . . . [Hobby Circuit designed by David A. Johnson P.E.,  12/08/13]

LED Driven Tail/Brake Light Cluster  -  LED driven tail/brake Light Cluster Constant current circuitry 12V Battery operation. . .  [Flavio Dellepiane's web site]

LED Driver Application for Portable Products See also DN23  -  MicroNote 1312s. . .  [Microsemi Corp]

LED Driver Combines High Speed, Precision  -  08/21/03  EDN Design Idea   Applications such as turbidity measurement and densitometry require cleanly pulsed light sources with stable Amplitudes. The LED driver in Figure 1 illuminates retinal neurons in a biological experiment that has similar requirement. . .  [by Richard Cappels, Mesa, AZ]

LED Driver Delivers Constant Luminosity  -  06/12/03  EDN Design Idea   White-LED driver touts high efficiency - The circuit in Figure 1 is similar in principle to that of a previous Design Idea   (Reference 1] but offers improved, reproducible performance. The output current is almost constant over an. . .  [by Israel Schleicher, Bakersfield, CA]

LED driver displays standing-wave ratio  -  03/18/99 EDN Design Idea   (Page includes several designs. Scroll to find this one)  The circuit in Figure 1 uses an LM3914 LED driver to directly display standing-wave ratio (SWR] in a low-cost, rugged instrument. The SWR-sensing head is derived from the ARR. . .  [by Richard Panosh, Vista, Bolingbrook, IL]

LED driver doubles as fault monitor  -  08/05/04  EDN Design Idea   LEDs find wide use as indicators and as light emitters in devices such as optocouplers. In some applications, the LED or the emitter may be located remotely at some distance from the main unit. Typical examples are dashboard-mounted automotive indicators and industrial optosensors. In critical applications, you may require some means of monitoring the integrity of the LED. . .  [by Anthony Smith, Scitech, Biddenham, Berdfordshire, England]

LED driver provides oscillator for microcontroller  -  09/16/04  EDN Design Idea   The major building blocks for a white-LED driver are an oscillator, a charge pump, and a regulated current source. National Semiconductor (www. national. com ] produces a device that contains all these building blocks in the highly in. . .  [by Wallace Ly, National Semiconductor, Santa Clara, CA]

LED driver provides software-controlled intensity  -  09/30/04  EDN Design Idea   Recent advances in operating efficiency have expanded the use of LEDs from one of mere indicators to becoming driving forces in electronic lighting. Increased reliability and ruggedness (versus other lighting technologies] gives the. . .  [by Neda Shahi and Bjorn Starmark, Maxim Integrated Products, Sunnyvale, CA]

LED Driver using Constant Current  -  LEDs are current driven devices. The light they produce is proportional to the current flowing though them. One way to maintain a fairly steady light output is to keep the current through the LED fixed, even as the supply voltage may change. A classic . . . [Circuit by David A. Johnson P.E.,  12/13/10]

LED Driver with 555 Timer  -  This simple LED driver circuit allows us to drive up to seven LEDs by using a single NiMH (Nickel Metal Hydride) AA cell. The circuit produces voltage pulses at a much higher level than the input supply voltage by pulsing the 220 uH inductor. The inductor must be a high Q (Q>90) power inductor. When the input is 1. 25 V and the. . .  [Circuit posted by Popescu Marian]

LED drivers minimize power dissipation  -  02/01/07    EDN Design Idea   Reference source and pullup resistor improve efficiency. . .  [by Fons Janssen, Maxim Integrated Products Inc, Bilthoven, Netherlands]

LED Driver-Wireless  -  The circuit solves this problem by sending power to the LED through the plastic, using a magnetic coupling technique. The circuit below can route power through plastic enclosures as thick as ¼ inch. The circuit will not work through metal boxes . . . [Hobby Circuit designed by David Johnson P.E.,  11/02/08]

LED Drives Flash-and-Beep Circuit  -  06/05/97 EDN Design Idea   Sometimes, you need an alarm that is both audible and visible in an application that's stingy with space, power, and budget. The circuit in Figure 1a is compact, efficient, and inexpensive. The F336HD flashing LED (part no. 276-036 at Radio Shack) is a useful device. . .  [by Dennis Eichenberg, Parma Heights, OH]

LED Flasher needs only 1.5 VOLTS  -  To squeeze even more energy from a alkaline battery cell, this circuit adds two transistors to a circuit similar to the above design to boost the efficiency. A small 1.5volt alkaline N cell should flash the LED for a full year. It too uses a "charge pump" technique to provide a LED the needed voltage . . . [Hobby Circuit designed by Dave Johnson P.E.,  06/03/00]

LED Flasher that is Battery Free  -  LED flashers have been used for a wide variety of applications. Some flasher units have been used in food and hardware stores, to draw attention to sale items and are often attached to boxes which dispense product discount coupons . . . [Hobby Circuit designed by David Johnson P.E.,  12/11/10]

LED Flasher Universal 3v  -  The electronic circuit below will flash any LED color with fixed current pulses powered by a 3v battery. It uses a charge pump approach, which routes a constant current pulse through the LED, regardless of the LED voltage requirement. Using this approach . . . [Hobby Circuit designed by David Johnson P.E.,  06/22/08]

LED Flasher-Wig/Wag  -  This simple circuit will flash two LEDs in an alternating fashion . . . [Hobby Circuit designed by David A. Johnson P.E.,  12/18/04]

LED Flasher-Wireless Circuit  -  When you would like to flash a LED through a thick plastic case without wires, use this hobby circuit. It performs this feat. It draws about 300ua of average current at 5v. It can be powered from a supply ranging from 3v to 6v . . . [Hobby Circuit designed by David Johnson P.E.,  01/09/11]

LED Flashing Badge #1  -  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 Dave Johnson P.E.,  03/26/02]

LED Flashing Badge #2  -  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 David Johnson P.E.,  03/26/02]

LED Lighthouse Flasher  -  This was originally designed for a model in a HO train set. It simulates the behavior of the light from a lighthouse. The LED intensity gradually increases, then flashes with a bright light and finally decreases slowly in intensity . . . [Hobby Circuit designed by David Johnson P.E.,  07/11/06]

LED Lighthouse Flasher for HO Model Train   -  HO train sets often have authentic looking scale model homes and buildings. The hobby circuit below can be mounted inside a model lighthouse. The electronic circuit drives a single LED lamp in such a way that it produces light which simulates the rotation . . . [Hobby Circuit designed by David Johnson P.E.,  07/11/06]

LED Pilot Light powered by AC Line  -  This 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 . . . [Circuit by David A. Johnson P.E.,  07/09/06]

LED senses and displays ambient light intensity  -  09/05/07  EDN Design Idea   Explains how an LED can double as a photosensor and a visual indicator of ambient-light intensity. . .  [by Dhananjay V Gadre of India's Netaji Subhas Institute of Technology]

LED Strings powered by AC Line  -  This shows 4 different ways to string white LEDs that are powered by a 120vac or 240vac power line.   The circuit was designed by Ken Schultz . . . [Hobby Circuit designed by David A. Johnson P.E.,  12/18/04]

Lens Drivers Focus on Performance in High-Resolution Camera Modules  -  Analog Devices-Analog Dialogue. . .  [by Casey, Gary and Conway, Mel and Murphy, Mark]

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