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LED (Light
Emitting Diodes) Circuits Page 4
LED: # A
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Last Updated on:
Friday, October 16, 2009 03:42 AM |
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Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
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Cascaded converter boosts LED drive capability - 08/16/07 EDN-Design Ideas: A
two-stage boost converter can drive a string of 20 to 30 LEDs.....(design idea added
09/07) |
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Charge Pump & Step Up DC DC Converter Solutions for Powering White LEDs in Series or
Parallel Connections - Maxim Application Note #1037 (app note added 11/06) |
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Chipiplexing efficiently drives multiple LEDs using few microController Ports -
11/27/08 EDN-Design Ideas: , "Chipiplexing" approach simultaneously drives two
LEDs.....(design idea added 08/09) |
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Christmas Decoration Project - This project flashes 18 LEDs at three different
rates and you can use these to create a Christmas decoration of your choice. The
circuit is kept simple (and cheap!) by using the 4060B IC which is a counter and
oscillator (clock) in one package. The circuit requires a 9V supply, such as a PP3
battery.....Designed by John Hewes (09/07/08) |
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Christmas Star - (electronic circuit added 10/05) |
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Christmas Star grantronics - (diagram added 05/07) |
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Christmas Tree - (electronic circuit added 4/05) |
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Circuit delivers dimming Control for White LED Driver - 10/28/04 EDN-Design Ideas:
The demand for power in color cell-phone handsets is constantly increasing. New
applications steadily emerge, making it imperative to reduce power consumption in the
design. Examination of usage data shows that more than 50% of the power consumed is in
providing backlighting for the color screen. People use the phones for playing games
and MP-3s and a multitude of other heavy-duty, multimedia f.....(design idea added
1/05) |
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Circuit Drives Latching Relays - 02/01/96 EDN-Design Ideas: (design idea added
3/03) |
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Circuit Drives Mixed Types & Quantities of LEDs - 10/03/02 EDN-Design Ideas:
Portable systems often use LEDs of different colors and in varying quantities of each
color. Some examples are white for the display backlight, green for keypad
illumination, and red for power. Typically, the LEDs derive power from at least two
power supplies: one for "standard" LEDs (red and green)and one for white LEDs.... |
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Circuit 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 substantially more than the sum of the LEDs' forward
voltages. The circuit is, therefore, marginal, to the point of being unusable, with a
5V supply and a red or green LED, which.....(design idea added 1/05) |
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Circuit uses Simple LED for Near IR Light - 09/01/98 EDN-Design Ideas: (design
idea added 6/06) |
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Clap Relay - Clap sensitive on-off Relay. 3V Battery operated, small
portable unit, (added 6/06) |
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Clock Design using the PIC16c54 for LED Displays & Switch Inputs - Microchip
Application Note Published 26-Aug-97 (app note added 6/06) |
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Color fade - Let's blink some leds again. Well, fading could be more accurate
term. Meaning of this article is to show you an easy circuit that lets you light up
your case with slowly alternating colors or just to make your power led come alive.
Color changing FireWheel could be also cool, what do you think? This is by no means a
step by step how to but I think that it will be enough anyway.(schematic / circuit
added 05/06/07) |
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Colour Shifting For Bi-Colour LED's - (circuit added 05/07) |
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Compact Inductorless Boost Circuit Regulates White LED Bias Current - Maxim
Application Note #1116 (app note added 5/08) |
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Complementary LED Drive - Microchip Application Note Published 6-Nov-98 (app
note added 2/06) |
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Connecting LED to PIC Micro I/O Pins - So, you’ve got a great idea for a project
using a PICmicro microcontroller and you want to use at least one LED in your project
as a power indicator. Or, maybe, you’ve set out to design a bar-graph voltmeter with
eight LEDs,....(electronic circuit added 7/03) |
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Constant Brightness LED Stroboscope: for Measuring the Speed of Small Motors -
The rotary switch is available for $5.00USD as of 2003 from DigiKey under part number
EG1951-ND or EG1952-ND. It is a real pain to operate this circuit without a proper
switch. You can put multiple 4017 ring counters in series to reduce the duty cycle in
order to obtain a more focussed strobe image but you will have to increase L or by
using a regulator to power.... (added 2/05) |
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Constant Current Constant Voltage Converter Drives White LEDs - 09/02/04 EDN-Design
Ideas: LEDs usually take their drive from a constant dc-current source to maintain
constant luminescence. Most dc/dc converters, however, deliver a constant voltage by
comparing a feedback voltage to an internal reference via an internal error
amplifier.....(design idea added 1/05) |
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Constant Current LED Driver - Bob Pease from National Semiconductor came up with
this circuit and I have used it many times. It maintains a constant current
through one or more LEDs. A single resistor controls the desired current.
….(designed by David A. Johnson) |
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Constant Off-Time Buck-Based LED Drivers using HV9910 - Supertex Semiconductors
(app note added 2/06) |
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Constant-Current DC/DC LED Driver in ThinSOT - Linear Technology LT1932 (app note
added 02/05) |
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Count To Ten With Lights - The circuit presented this month is a basic
configuration of the very versatile 4017 IC Chip. In the most common use of the IC, it
will turn on 10 separate outputs sequentially. Typically, the circuit is used to turn
on a LED….(added 08/08/08) |
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Create Secondary Colors from Multicolored LEDs - 07/24/03 EDN-Design Ideas:
High-speed current sensing presents a designer with some significant challenges. Most
techniques for sensing current involve measuring differential voltage
current produces as it flows through.....(design idea added 12/04) |
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Current mirror drives multiple LEDs from a low supply voltage - 12/05/08 EDN-Design
Ideas: , A pulsed current mirror comprising discrete transistors drives LEDs
from a low voltage, avoiding thermal runaway.....(design idea added 08/09) |
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Current Regulated Switched Capacitor LED Supply with Analog & PWM Brightness Control
- National Semiconductor Application Note LM2794/LM2795 March 2004 (app note added
02/05) |
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Current Regulators For Light Emitting Diodes - (schematic / circuit added 05/07) |
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