An LED is a light-emitting diode. Lighting an LED is considered the "Hello world" of a circuit design, and it can be as simple as putting a series resistor or can get more complicated, involving PWM and multiplexing.

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HOW TO CONNECT 100w LED IN TO MAINS 220V [on hold]

I wish to operate five of the LEDs shown below from 220 VAC mains. I have a limited budget and limited room for mounting so, the cost and size of a conventional transformer that would be required to ...
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34 views

How Transistor LED flasher circuit Works [duplicate]

I am learning electronics and have played with microtrollers and no a lot about basic circuits but I wanted to step back and create a solid foundation for designing circuits. So I was wondering if ...
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2answers
75 views

Change RGB leds intensity?

Sorry if this is too basic but I don't understand this issue. Right now, using an MCU, I change the RGB colours of an LED strip with 3 PWM signals. All colours works great . The thing is, when I am ...
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1answer
19 views

How to Swap Cathode with Anode in LED MATRIX 5X7 In proteus?

Hi in Proteus 8 the given model of Led Matrix 5x7 has Anode on Column side and Cathode on Row side. I want swap it and Hence Column would have Cathode and Rows will have Anode and my Second Connection ...
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2answers
60 views

2 LED Parallel circuit help?

I need to make a circuit with 2 leds, 1 green 1 red. If the current flows, green led will light up, if there is a break in the circuit (open circuit) it will light up another led as red. I don't ...
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120 views

How to make a computer with only copper? [on hold]

I have 60 lbs. of copper, and before selling, I intend on using all of its 60 lbs. of free electron movement to power a homemade computer. I would like to have MOSFETs connected to the copper ...
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2answers
35 views

Alternating between two LEDS using BJTs and SPST Switch

I made a circuit based on this post, Alternating between two LEDS using BJTs. It seems to work in the simulation just fine but when I'm connecting it with real components, I get funny behavior. ...
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44 views

Will this potentiometer control this led strip?

So first off I'd just like to say i know absolutely nothing about electronics. I want to add some lights to my computer case, will this work as a dimmer? 500K 1/2W Linear Taper Potentiometer White ...
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2answers
35 views

Momentary to Toggle Switch for Tiny Application

I need to put a circuit into a pen to turn on and off an LED using 3 AG3 or LR41 batteries connected in series. The LED will be on the tip of the pen and the switch will be on the side surface of the ...
3
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1answer
83 views

Strange LED behaviour

simulate this circuit – Schematic created using CircuitLab I have +9v connected via 180 ohm resistor to the collector of an NPN transistor. The emitter is connected via 680 ohm resistor ...
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2answers
43 views

Using a single inverter to turn a light off

I'm planning on adding two strips of LED lights to the edge of my headlight enclosure. This is obviously an aesthetic "mod" however I'd like it to be semi useful as well. I'd like to be able to wire ...
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2answers
44 views

0.5m of RGB LED strip light with micro RGB controller powered by 12v li-ion battery pack?

my questions are all pretty basic but I'm very new to electronics and could really use the help. Ill try and be as specific as possible and would appreciate any advice. Abit about me - Im UK based ...
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1answer
50 views

Running a 7v shift register from arduino 3.3v

Im trying to learn some electronics, so im not that confident with some of these systems, I recently bought a load of the alphanumeric displays from Sparkfun but foolishly read the data sheet for ...
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2answers
68 views

Driving LED using SN74HC164 and transistor. Apparently this schematic works but I don't understand why!

I am trying to create a project based on TI chip BQ78412 (Pb-Acid Battery State-of-Charge Indicator With Run-Time Display). There is an evaluation board whose schematic is published in this pdf on ...
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1answer
40 views

Phone charger project [closed]

I have a question, how to make a led that changing light from red to green and when the led turn green a buzzer will trigger? I want to make a phone charger project, that when the phone fully charged ...
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1answer
46 views

Basic AVR flashing LED program is not working

So I have begun with projects using AVR microcontrollers. A few months ago, I got one of these to simply flash an LED but I accidentally cooked that one with a bad power supply. Now I got some new ...
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1answer
46 views

Looking for advice on new led project

This is my first post, and I'm very new to the Hardware side of Making but I'm working on an led project and I need some advice. I want to use individually addressable leds, but my project is pretty ...
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45 views

What's up with this LED strip?

I have one of the common type LED strips that you put under a desk, or around a door, or wherever. It has the square panel-type LEDs that are common on these strips. I have a power cord that ...
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1answer
32 views

9X8 led array question

I'm completely new to electronics but want to build a blue light led array 8x9 with a 12V input and have no idea how to do this on a protoboard! If someone could help with a schematic it would be ...
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2answers
68 views

12 Volts or Nothing

Hello so I am hooking up a LED strip to my car but I am having trouble with the dimmer on the dashboard. To make this very simple and easy what I am trying to achieve is to cut off the power from the ...
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0answers
28 views

driver for 3 x 30 watt leds in series

I am trying to build a lamp using 3 x 30 watt led, a heatsink and hook them up in series to a driver. I have 220 volts outlet (Europe). I am a newbie in electronics Can someone help me choose a right ...
6
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1answer
194 views

Arduino IR Receiver

I was reading this tutorial http://arduino.cc/en/tutorial/button, and I want to do the same, but with a 2 pin IR receiver LED. The problem is, the LED needs 1-2v max, or it will break. How can I use ...
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0answers
58 views

First time enthusiast attempting to build a bottle glorifier with a single LED and battery for portability

I am attempting to make a bottle glorifier out of a single LED that will in theory last for a month without having to turn it off and run it off of some type of battery. That way i could change the ...
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1answer
48 views

rgb led current limit

I am working with RGB LED, my question is will it burn up / get damaged I have already chosen resistors proper for each color of R G B to draw 20mA, but running R G and B at same time draws lots of ...
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3answers
170 views

UV Led / Did I get Harmed?

There was an UV Led lying around, I wanted to check bank notes with it. I soldered a 3W led on PCB. And powered it with 4 AA batteries (connected in series) The light was bright and purple. (I mean, ...
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68 views

Connect lm386 to flash LED, dim light, poor sound

I'm really new. Not great in drawing schematics. I have a lm386 I want to connect to a tip31. I followed wherever I could online. 1. I tried it before the amp, so the sound became really loud and ...
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1answer
46 views

Trying to power a 100-watt Cree Xpe array as efficiently as possible with dimming

I've recently purchased a 100-watt Cree 30-module XPE multichip ...
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0answers
37 views

puprle acrylic guitar + super bright LED's = one confused guy

hi there i haver a wesley strat guitar with 3 single coil pickups i am in the process of fitting LED's internaly am currently using a 9v battery to run them what i would like to undertsand is how to ...
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3answers
172 views

LED with a transistor on each side

I'm trying to make a circuit with a transistor on each side of an LED so it only lights up when both transistors are activated. The transistors need to be on either side of the LED because the LED ...
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2answers
586 views

LED burnt out with 2x AA (or AAA) in series

Why does a LED burn out with 2x AA (or AAA) in parallel series, without resistor, but not with a single CR2032? Both are practically the same voltage, right? The led is a yellow from the Arduino ...
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2answers
50 views

Connecting resistor in LED parallel circuit

I connect 3 LED in parallel with a two AA battery source 1.2V each. As i searched in the web i realized that it is not correct to connect them without a resistor as they may get damaged. How mane ...
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5answers
65 views

Using Arduino-UNO to control LED pins Greater than the Number of I/O Pins

Our class have been given a project to create a miniature of our department building. It will have 11 laboratory rooms, 1 server room, 1 faculty room. Each laboratory room will contain 18 pc's, each ...
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2answers
23 views

Achieving higher current at the lowside MOSFET to pulse LED

I have attached the following circuits which i have been developing overtime. The OBJECTIVE is to get as high as possible a current at the gate of the MOSFET (VF1) to achieve faster pulse times of ...
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74 views

Making LEDs switch on at certain voltages as indicators

Is it possible to have a simple circuit that turns one colour of a two-colour LED on at one voltage and then the second colour on at a higher voltage. My concern is that if I size a resistor for each, ...
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2answers
75 views

Can I safely place a 60w between a 50w LED and a large heat sink that can dissipate 100 watts?

Today I have learned that Peltier devices can be used to generate electricity. I have a set up with a 50 watt LED which is glued to a very large heat sink that cools it without any fans (that can ...
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1answer
71 views

Read Values from a Speaker

I am using Arduino UNO and did a project to sync LED to audio. I am not sure how to read a value from a speaker. I connected a LED to Pin 9 (PWN) with 220ohms and ground. I connected A0 pin to a ...
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1answer
71 views

Request for guidance on sources to help me figure out how to do simple thing

I have 9 3w leds (white) and 2 1w leds (blue). I have one led driver with sufficient output to drive only the white leds (either in series or parallel.) Therefore, I figured I will get a separate ...
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3answers
47 views

Experimental strobelight duty cycle?

I am building an LED based low power strobe light. Currently it is running at 50% duty cycle, which is when I realised, it might not fully work, since if the light is on for half the time, the ...
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2answers
743 views
+50

Technology used in LED stumps and bails in WorldCup-2015?

I just know that when the bails are taken off from the stumps the LEDs will glow.Could somebody explain how exactly the concept works in case of LED stumps and bails which have been used in the ...
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0answers
45 views

Is it possible to produce 1 Hz flashes from a “joule thief?”

The joule thief circuit below produces a high-rate flashing LED. How can I slow the flash rate down to approximately 1 Hz? ...and will this be as efficient as a simple hex Schmitt inverter with a ...
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1answer
50 views

Another DIY Led Question (Complete Newcomer)…sorry

I have 10 Bridgelux leds (forward voltage 3.5 to 4.5v, drawing 750ma max). I also have a 36v Mean Well HLG Driver, offering 1.12a. It seems to me that trying to run all 10 leds (in series) is ...
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0answers
79 views

Connecting RGB LED light strip to LP3950 color LED driver

I want create color organ controller for use with 12V-24V RGB LED light strip. The LED light color changes need be synchronized to audio signal with both amplitude (beat) and frequency methods (4 ...
0
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1answer
16 views

Looking for a LED transmitter/receiver package(or group of components)

I am trying to design a system that utilizes 355nm and 370nm LEDs. I want to keep their intensity stabilized at a certain value, so I want to create a feedback loop. I am using these LEDs as ...
3
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3answers
74 views

Help Trobleshooting my first solderless circuit on a breadboard

I'm working on my first project from the book "Electronics All in One for dummies", chapter 6, book 1. I work through all the instruction but I cannot make the LED blinks. The circuit diagram is: ...
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1answer
60 views

PWM LED using TIM1 on STM32

I need to PWM my LED on STM32F3 Discovery which is on PE8. I have found code which is using PWM on PA8 and PC8 (one using TIM1) but unfortunately I can't change it to PE8. How to do it? Or maybe you ...
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4answers
102 views

How do I find out about the technical details of an LED if I don't have the fact sheet?

I have bought a bunch of LEDs from the rummage table of my local electronics store. Now, I don't have a fact sheet, neither I do know the vendor and / or the article number. How do I find out about ...
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3answers
70 views

Any way to create a 3 LED chaser with only a 555 IC?

I've seen single and dual blinking circuits, but wanted to know if there was some easy way to squeeze in a third? I don't have a 4017 IC at the moment, unfortunately.
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1answer
81 views

light up a 5v led with arduino

I need to build a big 6 digit display using 7 segment displays controlled with an Arduino, but the every display I find uses 5V LEDs like this one: ...
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0answers
40 views

Multiple led fade using charlieplexing at Arduino

Fading single led using charlieplexing is simple (example code). Is it possible to fade all leds independently? (I would like to fade them all simultaneously and randomly with different periods using ...
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1answer
40 views

Minimize Current Sensing Loss in LED Driver

Design voltages and currents: Vo = 100V. Iout = 50mA. Po = 5W. R4 is the output current sense resistor. The reference voltage for the error amplifier is 2.5 V which implies that under the target ...