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Questions tagged [led]

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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161 views

How to make LC circuit just using Capacitor and Inductor?

I am experimenting with inductor so I am looking for a simple circuit that will blink the LED with oscillator circuit. Basically turn on and off LED and finally diminish. How can I do so? For power ...
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3answers
40 views

How to use a transistor to drive strings of LEDs from GPIO pins?

This is similar to How to drive a 20mA LED From a 4mA max GPIO Pin except that I need a little more hand-holding in order to understand what is happening. For background, I'm a software engineer and ...
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2answers
82 views

Control the RGB tape with only one output of the microcontroller

I need to control the colors of an RGB ribbon. This requires 3 PWMs. But I have only one output of my microcontroller available. So for this I need to find a circuit that stays between the ...
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1answer
46 views

Light bulb LED equivalent of a CFL (Compact Fluorescent Lamp)

If I have a CFL light bulb of 100W what would be (how many watts ) its equivalent in LED. In the place where I live LEDs have taken over and CFLs are no longer available, but I need stron bright ...
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2answers
157 views

Running 20 WS2812 LED strips (80 pixels each) from a single Arduino and 24V Power Supply with Buck Converters

I am building a matrix with 20 WS2812 LED Strips. Each strip is 80 pixels for a total of 1600 pixels. I want to drive them all from a single Arduino Mega board. To handle the power needs, I have a 24V ...
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3answers
129 views

Make an LED (20 LEDs) circuit battery efficient

I want to wire up a miniature wargaming figurine to have 20 LEDs. As I've poked around options my concern is the battery life and how often the battery would need to be replaced. Since each gaming ...
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47 views

LED Project: IC that supports different flashing options [on hold]

I am an electronics newbie. I found a number of circuits that allow me to control 10 LEDs using the 4017 IC. The circuits basically allow me to cycle between the LEDs. Can anyone point me to an IC ...
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66 views

Ultra Low Consumption White LED Flasher

simulate this circuit – Schematic created using CircuitLab I need an LED flasher circuit to operate inside small model lighthouses. Ideally the flash needs to be white and the battery needs to ...
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2answers
151 views

Mystery! LED lights unplugged yet still lights perpetually

I got a string of LED Xmas lights hung behind my TV connected with an extension cord. I want to buy a power bar with a switch to turn it off but for now, I just unplug the strand from the extension ...
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2answers
152 views

Reviving / upgrading a commercial LED sign

I have a commercial LED sign that in its stock format is only controllable by IR remote (the remote is long gone). I'm trying to create a new controller for it so I can push data from one of our ...
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3answers
79 views

Basic resistor question for parallel LED circuit

I'm planning on building an LED circuit to place inside a model miniature for wargaming. The circuit would be in parallel as I'd need a really big battery to power up all the LEDs. I wanted to check ...
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1answer
58 views

Potentiometer min and max value

I purchased several of these to drive high power LEDs on a custom project : https://www.amazon.com/gp/product/B019W4C5IE/ref=ppx_od_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 These LEDs are to be ...
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1answer
118 views

Why is my led not on?

Hello I’m just a beginner and I made a simple circuit with a resistor and a capacitor with a led in between. As I understand the capacitor just accumulates the energy but why is my led not going on? ...
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4answers
188 views

Constant current source gets heated

I am trying to control some power LEDs using a microcontroller. For this I plan to use a transistor based constant current source to protect the LEDs from getting damaged and PWM on the base of the ...
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1answer
164 views

Arduino + PWM + LED Buck Regulator / Flashing not smooth

I am trying to use an Arduino + PWM to control a 100w LED using a Sure Electronics 300-3000ma buck regular - Product Here The chip being used is LM3409 The buck regulator is powwered by an external ...
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2answers
90 views

How does this LED string work?

I have a LED string with four different lights. The lights are in order red, green, yellow and blue and this pattern is repeated. It has a controller with a button to cycle through fading/blinking ...
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5answers
7k views

Why do some RGB LEDs have six legs?

Others have four legs, which makes sense to me, as ground can be shared. One of many examples of a six legged RGB LED is the Kingbright KAF-5060PBESEEVGC.
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1answer
163 views

Converting pre-lit Christmas tree with incandescent mini-lights to use LEDs

This might be a dumb question, but has anyone been able to successfully convert a built-in incandescent mini-light string to use LEDs? I have a few of these pre-lit burgundy-colored tinsel Christmas ...
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3answers
672 views

How do I figure which LED I need?

I need to replace two LED diodes on a TP4056 board (bottom right corner on the picture). The board is going to be in a box and I want to move diodes to the small holes in the box. There are two ...
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3answers
176 views

How to control multiple tiny PWM controllers with one “master” MCU; DIY LED array

My question is, how can I control multiple tiny PWM capable controllers, like this https://www.sparkfun.com/products/retired/8897, with one "master" MCU for the purpose of controlling LED arrays? ...
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1answer
174 views

Constant Current Led Driver (non dimmable) to work with PWM

I have 18W lamps that came with non dimmable led drivers. Ive found datasheet for the main chip (ws3441), which included schematics: and internal block scheme of the chip: I'd like to add dimming ...
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1answer
157 views

Would this Li+ flashlight circuit be considered safe?

I recently got an inexpensive (~$4 USD) Li+ 18650-powered flashlight from banggood.com, one of my favorite sources for inexpensive Chinese electronics to tear down and hack for fun :) I wanted to ...
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3answers
39 views

Multiple input to single output converter and vice versa

First question so please forgive any mistakes. I'm trying to design a system by which multiple LEDs are controlled by multiple switches, but without using as many wires as there are switch/LED pairs. ...
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0answers
70 views

What's the required voltage for ws2815? [migrated]

I am working on ws2815 led strip with the esp8266 on arduino 1.6.6 fast led library.Using CD40109B level shifter to convert 3.3V of esp output to 12V .It's working fine upto 31 leds according to the ...
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2answers
35 views

Can I in any way connect +ve side of my led to uln2083a output pin?If no can I do it with M54562 transistor array?

I had conneced my digital pin of arduino to the uln2803a to drive LED. I want to configure my uln2803a such that i can connect +ve side of the led to the output pin of uln2803a IC.
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1answer
15 views

Can a power surge have a different effect on a led driver when floating?

I have a LED driver which has 3 connections on the AC side , L,N and ground. In the event of power surge, can there be a difference in effect if the GND connection of the LED driver is floating or ...
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1answer
44 views

LED Package/Case

I could'not find the packaging searching online. Can you tell me the package/case types of the LED (right) and PD (left) below? Thanks in advance.
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1answer
82 views

Switch module test circuit design

I am doing a project to make a test box that would to test the switch module in the photo below. Please see circuit diagram below for inside of the switch. Please note this switch is not an ordinary ...
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2answers
167 views

Add constant current to an XL6019 module

I need to add a circuit to an XL6019 module to get a constant current (adjustable) source to drive some SMD LEDs. I'm no expert in complex circuits and my level of knowledge in electronics is basic. ...
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1answer
178 views

Switch/Pushbutton for Multiple LED String Lights

I'm helping my daughter with a science project. We're designing a glove for crossing guards with red and green LEDs attached. I thought it would be a good idea to put a small button in the thumb area ...
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2answers
769 views

Why does a 74HC595N work in LED matrices?

I have checked a lot of LED matrices, and mostly a 74HC595N shift register is used. In some cases a TPIC595B like below. Example: Driving LED arrays with Arduino Circuit from above example: I ...
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3answers
4k views

Powering mutiple Infrared LEDs through a single Arduino Uno pin?

I'm doing this project where I control an RC Car using infrared. Everything is perfect with 1 IR LED, connected to a 220ohm resistor. I'm worried about the range of the signal so I'm thinking of using ...
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1answer
169 views

Effect on LED driven at a higher Voltage than maximum forward Voltage

My current PCB configurations are (10 series 4 parallel)x3 in parallel making 10 series and 12 parallel I am using Meanwell ELG-75-42 driver giving a voltage of 42V at 1800mA, and a power of 75W. It ...
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4answers
17k views

Cool White LED bulbs: Are they “full-spectrum”?

I don't have much knowledge on LED lights and find the technology quite fascinating (yes, I know, it is not that new!) I have read that in order to create "white" light, LEDs actually need to emit ...
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2answers
109 views

Is the 100w LED I have really 100w?

I bought one of these: https://www.ebay.ca/itm/High-Power-Warm-White-DC-32-34V-100W-LED-light-Lamp-SMD-Chip-9000-10000LM-LM/272210214196 I am powering it with a 12v 8ah battery and a voltage booster: ...
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2answers
48 views

5W power led datasheet

Here is a 5W power led datasheet. I have several questions about it : What does "Peak Current (1 / 10 Duty Cycle, 0.1ms Pulse Width) - 1000mA" mean? Does that mean 1000 mA peak current is possible ...
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2answers
1k views

Using low-voltage halogen transformer for LED?

During a recent kitchen renovation, the electrician installed LED under-counter "pucks" and drove them with a 120VAC-to 12V, 40 kHz transformer labelled "low voltage halogen supply." I'm fully aware ...
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1answer
177 views

DALI DAPC OFF command

We are working on DALI LED control gear type product. We are using TPS92515 as LED driver and its controlled through Iadj pin (analog dimming). Our issue is even if we give input zero (GND) to control ...
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1answer
47 views

How much voltage I need to light up this led [duplicate]

I have a RL80-UR543 LED 8MM. How much voltage I need if I use a resistor of 100Ohm?
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1answer
71 views

RGBW Cree XM-L LED power circuit HELP!

I have 10 Cree XM-L RGBW LEDS and I would like to power them from a 12V power supply. I came up with this idea: A 12V 30 amp power supply powers 3 different step down buck converters (10 amps each ...
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0answers
28 views

Problem with 5 meter LED strip light and 450W power supply [closed]

I build LED strip lights using old florescent shop lights metal reflectors and used as the heat sink solution for the strip stick on LED light. Total of the LED strip was about 6.5 meters and I ...
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1answer
57 views

Why does this dimmer switch have reduced wattage capability for LED / CFL bulbs?

The Lutron "Maestro C•L" dimmer has different wattage ratings depending on the type(s) of bulbs being controlled. Its an electronic dimmer. Specifically, when 100% incandescent or halogen it can ...
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2answers
338 views

Strange issue with signal noise WS2812B [closed]

I have a LED strip cut to size for the upper cabinet but it's having issues displaying the correct colors. When I touch any of the contacts with my hand everything works correctly but if I let go it ...
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2answers
2k views

Do I need to replace the transformer when switching from halogen to LED

Total noob question. I have MR16 halogen downlights and want them replaced with LEDs. Someone told me that, if I simply replace the bulbs but not the transformer, then the power draw will still be ...
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1answer
955 views

ATmega328p driving RGB LED WS2801

I am using an ATmega328p to control this RGB LED module. The ATmega is on an Arduino Uno, but I am programming it in C, without using the Arduino libraries. To power the RGB module I am also using a ...
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2answers
39 views

USB switch matrix switch to control an externally powered LED? [on hold]

Is there a way to wire the lighting on an illuminated switch so that it's powered by a separate dedicated battery and NOT by the matrix encoder device that the switch is a part of? I have a USB ...
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1answer
284 views

To use a Dual Voltage Electric LED Bulb E26 in a E27 environment/ socket?

To use a Dual Voltage Electric LED Bulb E26 in a E27 or B22 environment? So I bought a Universal LED Bulb that emulates Circadian Rhythm for lighting to help manage my sleep cycles, locally (wherever ...
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2answers
58 views

Is it safe to use LED transformers with existing 12v halogen bulbs? [closed]

I am in the process of installing two "Tech Lighting" pendant kitchen lamps (each with their own transformer, but on the same dimmer switch). My question is: Can I use MR16 gu5.3 50w 12v halogen ...
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1answer
59 views

How to choose the right potentiometer for dimming a LED

I have a reading lamp from IKEA. It has a bright LED. Too bright for my taste. So I inspected it and it is composed of a DC power supply unit that outputs 7V and a maximum of 3W. The LED unit is ...
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2answers
3k views

Heat Transfer of Aluminum Plate with LEDs

I'm building an LED grow light for an, um, indoor vegetable garden, and I'm trying to figure out what dimensions I can get away with for the aluminum sheeting I'm going to use for the mounting plate. ...