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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3answers
82 views

LED brightness stability issues - how to fix?

I am performing an imaging experiment in which LED stability is critical. I use 2-3 red LEDs to illuminate a surface while imaging that surface. In each LED circuit, I use a constant-voltage ...
0
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1answer
50 views

Using a Computer PSU for its 12V output for high wattage loads [closed]

I'm looking to install some LED light bars (primarily designed for use on off-road cars) as fixed outdoor lighting on my property. I see they have models that use up to 700+ watts of power (for crazy ...
4
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3answers
899 views

Resistor Selection to retain same brightness in LED PWM circuit

I am making a simple LED PWM brightness control circuit. I am using a relatively high power White CREE LED, N-channel Enhancement MOSFET BSS316N and Resistor R. The circuit is as shown below. I am ...
0
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2answers
59 views

What battery size/type should I use (and wiring tips for LEDs?)

My son and I are designing a 3D printed body for his pinewood derby car. We want to add some colored LED lights. I found some lights that I think will work well, from a mechanical fit and looks ...
2
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1answer
93 views

Directly connecting LEDs to IC outputs

Forgive the amateur question - I don't know anything about electronics. I was not able to find any similar questions on this board, but that probably has to do with the fact that I know so little ...
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3answers
146 views

Will this schematic work - basic LEDs + strips

This is my first LED project for my art bike and after a good chunk of reading, I wanted to know if the circuit would run properly. LED are green 5mm from AliExpress. Forward voltage 3V-3.2V, 20mA ...
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1answer
72 views

Led cube 4*4*4 with anodes horizontally

I want to create an Led Cube 4x4x4 with an ATMEGA 16 chip. Because is my first electronic project, I connect leds on layers(horizontally) with common anodes and vertically with common cathodes. ...
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1answer
55 views

LPC1768 - Green LED when LDR sees light, Red LED when LDR is covered

I have been trying to achieve a task I am working on and I believe I am almost there. It successfully changes colors whenever I cover it but when it does, the red LED keeps blinking instead of it ...
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0answers
41 views

Led driver compliance voltage

I want to design a led driver providing constant current to relative high power LEDS such as CREE XLamp series. These LEDs typically can be operated with 1A and upwards with a forward voltage of 12V ...
0
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2answers
101 views

I'd like to add one more LED (1->2) but don't know how to keep the same current

I made a simple LED circuit using a battery, a variable resistor, and a LED. When the light intensity satisfied my demand (I do not need the full intensity) by changing the resistance, the condition ...
29
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2answers
3k views

Why can't RGB or bicolour LEDs produce a decent yellow?

I have several different RGB LEDs and bicolour red/green LEDs, from different suppliers. I find that, with the appropriate resistors, they can produce a perfect orange and cyan; and a barely ...
0
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1answer
87 views

How to remove flickering on car-powered LEDs?

I am powering an array of LED lights via the car alternator (the LEDs are connected to the car battery leads, but only run when the engine is on). The problem with this setup is that the natural ...
0
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2answers
58 views

PIC32 UART TX working perfectly RX not

I am using PIC32MM0064GPL028 to drive RGB+W LEDs via TLC57911 LED drivers. The idea is - data from python script -> Easysync USB to RS-485 -> ST485ECDR transceiver -> PIC32MM0064GPL028 -> TLC57911 -> ...
0
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1answer
61 views

How to improve flash time on lights controlled by solid-state relay via Arduino?

My goal is to flash lights around the house on and off to the beat of a song. When doing this with a mini LED and an arduino, it works perfectly with a "flash_time" of ~.1 seconds. This means ...
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1answer
78 views

One led is blinking too frequently using the hardware timer (stm32f103vdh6)

i recently started my internship using embedded C and i'm having some trouble with one of the tasks: Two leds should be blinking at 1Hz, one using the hardware timer, and the other one using the RTX ...
0
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1answer
101 views

Calculate transistor collector and base resistors values for driving LED with GPIO

I try to learn how to use a transistor and how to calculate the necessary resistances. Here's what I calculate for the moment. I do not know at all if I left properly and if my equations are good. I ...
0
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4answers
174 views

red led has turned off but conduct current

I have some LED modules powered with 12 VDC. Each module has 3 LEDs and 3 resistors all in series. After working for one year, in some modules, one or two LEDs turned off but another one is on. I ...
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2answers
35 views

Explain how this astable chain(?) circuit works

The circuit below fades on and off a cascading series of leds in an alternating fashion. I tried reproducing it on a breadboard with 5 leds to try to understand it how it works, and got all sorts of ...
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2answers
49 views

3 volt string led light adapting to 5v usb charger source

I would like to cut off the batteries, and light these 10 led string light with 5v usb. I dont know how much current flows throught them, and dont know what resistor should I use. Please help. Im a ...
0
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1answer
60 views

LED driver putting out more voltage than rated?

The Background I bought a 200W magnetic LED driver with hopes of replacing the 40W Philips-supplied driver that came with my set of Hue Lily outdoor lights. Each fixture requires 8W at 24v. This new ...
1
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4answers
95 views

Supply white/blue led with 3V3 at constant current

I need to drive a white/blue led at low constant current (about 10mA.) To do that I usually use the schematic below, but in my case I can only supply the LED with 3V3. Since the typical forward ...
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0answers
60 views

TV Backlight LED's voltages

I have a power supply that is outputting ~300v and 350ma. the LED's in the backlighting are on 11 strips and there are 6 per strip. Can I calculate the voltage per led by dividing 66 LED's into 300v? ...
2
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0answers
66 views

What LED PWM controller has marking AT508CS?

I have an LED worklight with low- and strobe-functions. One click: On - full Power Two clicks: half Power Three clicks: strobe Four clicks: Off The controller is circled: No markings on the top ...
0
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1answer
46 views

Constant Current Output driver connected to 2 COB LEDs - is the hookup valid?

I have a lamp with this hookup. Can someone confirm whether the electrical specs match up such that these can be connected in this way. ld009d-cu03036-m9 - MagTech Constant Current 24-36v output ...
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1answer
82 views

Why use a transistor to drive an LED?

Why I should us a transistor to drive an IR LED? I see many schematics which use the following circuitry: If I connect the IR LED directly to an Arduino digital pin, it works. But with the ...
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2answers
61 views

LEDs sharing negative output from driver issue

I am having an issue with the above circuit when LED DRIVER B has 0 PWM and LED driver A is being driven by a signal driver B is supposed to be off but the leds from BANK B are still lit dim. I ...
0
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1answer
51 views

Leds blink with a different power supply

I made a led circuit in parallel with a power supply of 12v 2a. But there is the problem, I’ve changed the power supply. Still the same value of 12v 2a but my circuit doesn’t work. I’ve tried a lot ...
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0answers
63 views

Flickering Neopixels (WS2812B)

I am working on a WordClock. First, I want to give you all the details needed and then I will ask my question. So, for this WordClock I used the Arduino with the FastLED library. I made a PCB (350 x ...
4
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2answers
489 views

How to reduce LED flash rate (frequency) [closed]

I have purchased an LED flasher circuit from Ebay (see jpg) for use on a model plane, but the flash rate on the circuit is much too fast, about 4 flashes a second. I am trying to achieve 1 or 2 ...
1
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1answer
44 views

Improving load regulation on voltage regulator

Basically, I'm building a device that powers a number of LEDs; each LED needs to have as consistent a power as possible (each eats 25mA at 3.3V) across the number of LEDs being lit up. I'm using a ...
0
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3answers
76 views

Proper resistor(s) for limiting LED brightness

I have an LED powered by a serial(Rs-232) port on my PVR. The light is connected to the DTR pin through a 1k\$\Omega\$ resistor. It is set up this way in accordance with the instructions for the ...
0
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1answer
41 views

IR Remote with 4 buttons timer

So I was wondering how it would be possible to design an IR remote that consists of four buttons for each channel powered by a battery. How would I be able set something like this: The receiver will ...
3
votes
1answer
118 views

SMD LED: How to calculate optical power (in mW) from luminous intensity (in mcd)?

I chose an LED for my application but I need optical power, in mW. In the data sheet, luminous intensity is shown in mcd but I did not find formulas for calculation although there are graphs, etc. ...
0
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1answer
55 views

555 timer square wave LED flasher

Will this circuit work for the purpose of making a high voltage LED flash on and off at 10kHz? I have a NPN transistor to turn the LED on and off. The pad is where the LED will be soldered into as ...
3
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0answers
37 views

How to wire an entire room / kitchen with LED light strips? [closed]

As the question suggests, I'm looking into adding LED light strips throughout the kitchen (over cabinet, under cabinet, and kick -- I think under the countertop would be neat, but harder to hide). ...
27
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11answers
7k views

How can I wire a 9-position switch so that each position turns on one more LED than the one before?

I have a 9-way switch like this guy: And I'm trying to figure out how I can turn on one LED with position 1, 2 with position 2, all the way up to all 9 in position 9. Obviously I can repeat all the ...
0
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1answer
56 views

How to find the best way to fade in/out?

I have a bunch of these PAR lights below. They work with DMX and have per LED PAR 3 red, 3 green, 3 blue and 3 white LEDs. I can set the value for the red, green, blue and white lights independently (...
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4answers
105 views

How do I remove resin from an LED?

I want to get direct access to the top contact of an LED. How do I remove the layer of resin on top of the LED?
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2answers
105 views

Calculate run time for leds

I have 8, 5 watt LEDs that run from a 12VDC source. 3, 18650 batteries at 3000mAh each. I want to know the approx run time of the LEDs. Thanks.
0
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1answer
103 views

Can anyone tell me what the IC is?

I am working on the re-design of an old board, but due to many reasons, the original design document is incomplete. So I sometimes have to figure out what an IC is. Here is one I couldn't figure out, ...
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2answers
85 views

Will a resistor allow the battery to last longer?

3V 25mAh button cell battery, a single 3-3.4v 20mA UV LED. If I put a 1/8W 1 ohm resistor in the circuit will the battery last longer?
0
votes
1answer
111 views

Zener diode question in simple LED circuit with anti-flicker for model railroad

I am a total novice when it comes to electronics. I had a simple circuits class 30 years ago as a software undergrad. I've designed a simple LED lighting circuit for N-scale model railroad, to be ...
1
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1answer
29 views

Buck Converter and WS2812 LEDs

So to start off I am powering 70 LEDs through a 24V 6A power supply. The WS2812 LEDs require 5V operating voltage and about 50mA at their brightest setting (white light). I'm having this really ...
1
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1answer
38 views

Replace 5mm LED with High Power without changing the circuitboard

I would like to know if I can replace the LED on my radar detector remote controller with a high power one without changing the circuit board components. Attached is the board and I'm looking to ...
0
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0answers
43 views

Is there a way to have the LED switch on after 10 readings or say a minute?

I am using Arduino for a RFID project where the LED must switch on after either 12 readings of the tag or 2 minute, the tag reading happen every 10 seconds. I can't seem to figure out a way to have ...
0
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1answer
44 views

Determine polarity of IrED with multimeter

I have an infrared LED as part of an IR transceiver, and I want to determine its polarity. As the device is unmarked, finding its datasheet is out of the question. And, as it is infrared, seeing it ...
1
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2answers
90 views

Micro:bit LED control using P30N06LE

EDIT: My reference in this question to analogue voltages are just how my voltmeter reads and averages the PWM from the Microbit. Apologies if I'm confusing the matter with this. The project is using ...
0
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6answers
92 views

How to alleviate the negative effects of using parallel LEDs with a common resistor?

We all know the rookie mistake of using LEDs in parallel and not giving them separate series resistors. They are often doing it for ill-founded incentives like "I want to save money on resistors", "I ...
3
votes
0answers
40 views

7030 SMD LED pad configuration

I have not done a lot of work with SMD LEDs and have a question about the pad layout. I have done quite a bit of research and haven't found much helpful info yet. I am working with 7030 SMD LEDs ...
2
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2answers
35 views

Power 9 IR LEDs 850 nm with a forward voltage of 1.7 V and forward current of 100mA

I am looking to power 9 IR LEDs 850 nm with a forward voltage of 1.7 V and current of 100mA. i want to make a circuit where i can use a small power supply or could I use the raspberry pi to power it? ...