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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Arduino Motor and RGB LED problem

A few weeks ago, I was working on an art project and it involved both spinning a stepper motor and driving some RGB LEDs through PWM using an Arduino UNO. Both functions worked fine on their own, but ...
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36 views

Powering lights using an rca cable

I am trying to power 12v LED lights in my car but I would like to have them sync to my subwoofer. Obviously tying them directly to the speaker wire terminal is out of the question because the amp puts ...
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1answer
46 views

How long will my batteries last?

I've read some of the other questions and answers hoping to understand well enough to resolve my question without posting it, by I have no real knowledge about electrical engineering and so some of ...
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2answers
90 views

Lighting a LED with only one wire

It might sound stupid but is there any way to light a LED using only one wire? I mean, can you use a capacitor or something similar on the other pin of the led to "close" the circuit. Keep in mind ...
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2answers
58 views

30V adjustable current LED driver

I've recently started a project that has some pretty loose specifications. I need to develop an LED driver that can take an input of somewhere between 7.2 and 24V, and drive an LED panel at 30V with a ...
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1answer
37 views

12volt LED used with 12 volt, 6A power supply.

Thank you for reading and thinking about this: there is some unknown factor here. I need to use an LED to light an area of a device. The device has a 12v, 6A power supply. I was expecting to have to ...
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1answer
47 views

14 x 14 LED Matrix - How can I control it?

I intend to build a 14 x 14 standard 3mm blue LED matrix, for a WordClock-like project, but I have no idea how to control it. I've heard of multiplexing with NPN transistors, but I'm concerned about ...
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1answer
37 views

How do I wire LED light based zone for DALI dimming?

I understand the concept of DALI but I’m having problems understanding how to wire a zone. Let’s say one of the sections of my living room will have 5 x 5W /350mA ...
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1answer
37 views

Can I connect various LED fixtures to one driver?

Let's say my driver is 32W (700mA). I should be easily able to connect 5 x 5W 350/700mA LEDs right? My idea is to use driver with DALI interface and control 5 LED's using just one address.
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38 views

Visible Light Communication. Unable to Receive Square Wave Signal at the Receiver [on hold]

I am having trouble receiving the sent 1 MHz square pulse sent by the LED to the photo diode. Could you please let me know what needs to be changed in order to receive a similar signal.
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40 views

circut.diagram , calculating voltage drop and how many ohms resistors are needed [closed]

for 5 white, 1/2 watt leds with a power supply of minimum 5 volts ..how many resistors and how many ohms each a resistor would I need .....please draw a circuit diagram with the given details and ...
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2answers
74 views

Effect of LEDs in series instead of parallel with resistors

So I have two LEDs with a Forward Voltage rating of 2.65V each. Would I be okay in hooking them up to a power supply of 5v in series rather than in parallel with resistors? I'm asking mostly because ...
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1answer
76 views

How to connect a 3 PIN photo-diode ? Specifically Hamamatsu S5973-03

I am trying to receive a 1MHz square pulse generated using a LED. But the square pulse I get from the photo diode is extremely distorted. I am unsure about the way I am connecting the photo diode. ...
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1answer
36 views

PSU with dc stepdown buck

I want to connect different LEDs that have these parameters (the LEDs I am using are just generic LEDs I got from ebay.): Led 1: 6.4V - 7.2V @ 0.7A Led 2: 2.9V - 5.6V @ 1.9A Led 3: 8V - 12V @ 3.4A ...
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1answer
63 views

12V regulator for 100W LED

I want to make a 100W high power LED headlight for bike, but the problem is that LED releases a lot of heat, and I'm using a 150W boost converter to convert 12V to 30V ( minimum operating voltage of ...
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1answer
50 views

High Power LED and relay with the same power supply

I'm rebuilding optical printer (the machine which does Super8 to 16mm film blow-up) and designed new electrical circuit for it so I can control it with Arduino (or maybe later with Raspberry Pi). ...
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0answers
36 views

Wiring of 0-10V LED Dimmers

I will be installing (well, my electrician will) LED lights at home with these specifications ...
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1answer
52 views

led voltage and current relationship via a driver

I am trying to understand what happens to the voltage supply to a high power LED when using a Constant Current LED Driver. Things I (think I) Know: -An LED has a certain range of operating ...
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3answers
42 views

Matching appropiate current value for components

I was looking around the site and I encountered an intresting answer.The one who posted it said that:"If you supply too much current to a device,it will draw as much as it needs" and also that if you ...
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1answer
47 views

Current saturation

I have bought a bunch of 24v LED for the garden, during the first months all of them worked fine, but some after they burned out the power supply. The reason is because they were demanding high ...
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2answers
162 views

Understanding this LM317 LED Driver circuit

I came across this simple LED Driver circuit ( I am aware of the power losses but just wanted to understand its working) . Now in a Voltage regulator configuration , ADJ is connected to a voltage ...
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3answers
78 views

One resistor on two LEDs [duplicate]

This question is a little bit stupid and silly. As I am chemist, I don't remember electricity physics very good. As I remember it shouldn't harm anything, but I need to be sure. LEDs will be ...
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1answer
48 views

capacitor for led strips

I want to make a DIY Power PUC to put led's on my motorcycle. I plan to use 5050 RGB strips. Power supply to these LED's will be in the form of a carbon brush - aluminium ring assembly. But since the ...
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0answers
57 views

Unsure of why this two-transistor LED flasher circuit isn't working

Over the years, I've been using a RadioShack Electronics Lab and project manuals to learn more about electronics. I cannot understand why one of the projects I built does not work as intended (that ...
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0answers
184 views

Do LED lamps need a bulb? [migrated]

I bought an LED light bulb on eBay, which unfortunately is too big for the lamp i want to put it in. If I would remove the glass bulb however, it would fit. My question is, does the lamp actually need ...
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2answers
51 views

Proteus Circuit LED does not work

I am trying to build a double dice circuit. I tried one example I found from the web. But, I have problems with leds, and I am not very familiar with proteus. Could you please tell me why my LEDs ...
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1answer
71 views

Interfacing switch and LED

I am trying to write a program in which I am interfacing a switch and a LED. I want a program so that when I press the switch the LED turns on and when I press again that led turns off. Right now I ...
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1answer
26 views

LED Music Visualizer on Headphones

I am currently trying to make an LED music visualizer that goes to music and attaches to my headphones. The ideal solution would be to have the LEDs run from the audio circuit from a smartphone (with ...
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1answer
62 views

Illuminating the wall of a transparent tube

I have a plastic tube that has a wall thickness of around 3 to 4 mm and it is transparent. I am trying to build a ring for the top of the cylinder that just illuminates the sides of the tube, but ...
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1answer
115 views

Transistor inversions

Having some trouble with transistor logic. I have an existing circuit with a 3.3V rail and signal rail that is pulled to 0V when asserted, i.e. active low. I ultimately need to control four 12V LED ...
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0answers
34 views

Trouble splitting off LFO signal to drive LED

Background: I am trying to build a very simple noise box that doesn't need to be tuned to 1V/Oct or anything special. It simply has one VCO, two LFOs, and a VCA. The circuit is powered off of a dual ...
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1answer
63 views

How to wire many bi-color LEDs to a single power supply, and switch them on/off individually

My goal is to have 13 separate stations, each with a bi-color, common cathode LED (Dialight 606). These LEDs do not require external current limiting resistors. Each LED can be 'On Green', 'On Red', ...
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0answers
68 views

LED Light Trains

G'day, I'm building a table at the moment and I've got old school PCB and components all over it and a 'Danger High Voltage Keep Out' sign in the centre. I had the bright idea of wiring up an 9V LED ...
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3answers
72 views

How to reduce the voltage dropped in a mosfet used as a switch?

I'm trying to use a N-channel mosfet as a switch for controlling a LED, but the most of the voltage is dropped in the mosfet itself (drain-source) and the led are not turning ON. The voltage in the ...
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1answer
41 views

step down switching frequency

If I have a power supply that outputs 32V,7A and I need to power an LED that requires 24V-2.8A, can i use this step-down module to power up the LED? ...
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1answer
35 views

MIKROE-55 - LCD Datasheet [duplicate]

I'm a bit confused by the datasheet of a LCD (MIKROE-55). It says supply voltage is 3.5V (TYP), which results in as Supply current of 16mA. At first I understood this as: "connect K to GND and A to ...
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1answer
41 views

WS2812B with ATMega8 and light_ws2812 Libray

I have connected four WS2812B modules I got from eBay to my AtMega8 and tried to use the light_ws2812 libray to controll them. I connected the wire used for communication to the PC5 Pin on my ATMega ...
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1answer
99 views

Infrared LED vs halogen light output comparison

I am thinking of using a high power ~50W IR led. I am wondering if LED IR is more efficient than halogen as is the case with visible light LED's? I couldn't find the light output of either IR halogen ...
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1answer
16 views

TLC5916-Q1 LED Driver Serial interface

I am planning to use TLC5916-Q1 LED Driver for switching of 8 different color led's and in application,switching takes place at fast rate. Datasheet: http://www.ti.com/product/TLC5916-Q1 For ...
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4answers
137 views

Slow slew-rate of photodiode circuit output

I've built an LED driver and a photodetecting circuit. Basic forms of the driver and the detector were made. Driver Detector FYI: Parts used and their datasheets LED: Seoul semiconductor ...
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2answers
52 views

Keep brightness high whilst multiplexing [SOLVED]

I have searched a little but I'm a noob to electronics so it was hard for me to understand. So here is my problem. I have made a little 3 x 3 led matrix to test. When powering 1 led it was fine, but ...
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1answer
60 views

Heating Nitinol while driving LED

Edited in my LED module current requirements, fixed needed resistance and added a schematic to better illustrate what I'm trying to do. Thanks Tom and asmydolf. Okay, it might seem like a dumb thing ...
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1answer
50 views

switching power redundancy

I have a load (LEDs) that draws 36V, 5A. The circuit is made in this way: Power Supply (AC-DC) -> LED Drivers (5 in parallel) -> LEDs (5 strips). What component I need to install if I want to add ...
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1answer
30 views

Controlling LED Bulb Dimmer via Microcontroller

I have several (Cree LED bulbs) that I would like to dim via microcontroller. According to Cree the bulbs are dimmable with compatible dimmers. A local hardware store here in Canada has one of the ...
3
votes
1answer
186 views

How many ohms do you need before you need a resistor?

Okay, I'm rather a bit confused here now. I am trying my first real circuits, for some LED lighting. I tried making a little circuit last night, matching two LEDs in parallel on 4.5v of battery. ...
11
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3answers
706 views

Why does the intensity of light in LEDs not increase with current after a particular value?

I read in books that light intensity from an LED does not increase beyond a certain value of current. The amount of light emitted depends on the combination of holes and electrons. If so, then as the ...
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0answers
50 views

Would this power supply work for this config?

I have looked around on the forum but could not find an answer specific to this issue. I have 8 parallel LED strips, each works at 30-33V and requires a constant current of 0.7A. I have a power ...
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1answer
40 views

Power Supply for 555 Timer LED Fade In/Out

I am a complete electronics newbro. I am looking at building a small circuit for a couple of home made modelling projects. I am following ...
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2answers
85 views

Limit current with fewer resistors

Arduino digital pin in OUTPUT mode have low impedance, is it safe to limit current through two leds (connected to two output pins) with one resistor, not two (knowing that leds will go dim and current ...
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1answer
37 views

Small Footprint Single Pulse 500ms per minute LED 3.3v

I'm quite new to electronics, so hopefully I don't offend anyone by asking a question badly. I'd like to make a circuit that uses a CR2032 (3v) button cell to pulse an LED (3mm blue clear super ...