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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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1answer
48 views

9 volt battery and a 10 watt IR LED [on hold]

I connected a 9V battery to a 10V IR led and the brightness lasts 3 seconds before "dimming" down to a soft glow. How do I maintain the initial brightness? Do I plug in a few AA or do I buy a 30 or ...
0
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2answers
73 views

Connect 10 LEDs using 5 volt current

I have 10 yellow-colored LEDs and ten 220 ohm resistors. I don't have any power source except the Arduino's 5 volt itself. Is it possible to power all the 10 LEDs using the 5 volt equally? Or will ...
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0answers
42 views

Adequate Power Supply for 300 Daisy-Chained LEDs [on hold]

I have 300 LEDs (ws2812b) wired in a series. They were sold as 150 LED/5 meters and rated to power at 9W/m, so 45W/5m strip. I would need 90 Watts to power my entire 300 LED strip. I have a 3-rail ...
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3answers
25 views

Adequate Power Supply for 300 Daisy-Chained LEDs

I have 300 LEDs (WS2812B) wired in a series. They were sold as 150 LED/5 meters and rated to power at 9W/m, so 45W/5m strip. I would need 90 Watts to power my entire 300 LED strip. I have a 3-rail ...
1
vote
4answers
39 views

Normalised Current Transfer Ratio of Opto-Coupler

My understanding is that the Current Transfer Ratio of an opto-coupler defines the relationship between the current flowing through the LED, and the maximum supply current of the output. e.g. "5ma ...
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0answers
25 views

Mountain Bike Light Bar 18650 battery pack

I have a 6 Inch LED Spot Mini Bar Light which is used for vehicles, it uses 12-24 V and is rated at 18 W of power. I have some 18650 batteries which would work perfectly for this project. What would ...
0
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1answer
64 views

How much battery power for LED and how to make it flicker

I am trying to figure out what configuration of battery(ies) I need to power this LED. I am only using one (specifically the warm white 1-up). I am also looking to make it flicker like a candle with ...
0
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1answer
49 views

Uneven LED Lighting Wired in Series

I’m struggling with six 11.5-watt LED cans wired in series. With a 75-watt incandescent at the end, the other five seem to function properly, though the incandescent is dull. With an LED in its place, ...
0
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2answers
37 views

24V signal switching optccoupler

We have a robot, and it has 32 digital output, fed into a homemade PCB. On the PCB we have optocouplers, which have a forward voltage around 1.2-1.3V. So I need to drop the voltage a lot. That's why ...
0
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0answers
33 views

LED drive circuit (PFET) turning ON by itself

I thought 10k pull-up would prevent LED from turning on, but when I connect +VBAT (4V) and have D_LED_S_W floating the LED turns on slowly (in few seconds). When this happens the gate voltage starts ...
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0answers
20 views

Does my PWM led circuit controlled with NodeMCU and Mosfet work properly. What should I do to improve it? How to calculate for each components?

If I understand it right, when there's is signal from ESP, the PNP and NPN be ON, and Vgs=0. If they're OFF Vgs=+12V and the LED will shine. R=1K is to limit the Ib of NPN, and R=10K is the resistor ...
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1answer
41 views

Building Led light which work on 230V supply

I have a couple of 9W LED bulbs(1) at home with blown drivers. I got some replacement boards(3) with driver circuit and LEDs on the board itself. Now that the old LEDs(2) along with the aluminum PCBs ...
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0answers
12 views

How do I wire in a capacitor into an LED circuit to eliminate a flicker issue? [migrated]

I have led running lights on my truck (with a resistor already inline) and am encountering a flicker issue ONLY when the engine is running. I was thinking a cap would fix it.
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3answers
47 views

Epoxy Resin Molded vs Hermetically Sealed Metal Can Packaging for LEDs and Photodiodes

Between epoxy resin molded vs hermetically sealed metal can packaging for photodiodes and LEDs are there any relevant functional differences I should be aware of when selecting between otherwise ...
4
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1answer
165 views

Understanding a PNP/NPN LED schematic

I bought and soldered a dirt-cheap flashlight kit from China. I'd like to understand how it works, though - specifically, why it uses a combination of a PNP and an NPN transistor (schematic from the ...
0
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0answers
28 views

How to calculate R1 and R2,? How do Mosfet IRF540 and ESP work in the circuit

So the 3.3V PWM signal from ESP is sent through R2 to the Gate to breakthourgh the Vgs(th) to make Mosfet ON, and the author of the circuit say Gate is pulled high to 12V by R1. But I don't understand ...
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0answers
56 views

LED bulb drivers, reason why led bulb would not illuminate in relay circuit [closed]

I have a liftmaster circa 2008 garage door opener, two in fact. Incandescent bulb went out on my side. bought 60w LED buld 2 pack from depot for $5 I put new LED bulb in liftmaster, does not ...
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0answers
9 views

High frequency driver IC/circuit for ToF LED [closed]

I am looking to build a ToF camera with IR LEDs. I have found LEDs that seem to fit the purpose, fast LEDs from Lumileds. https://www.lumileds.com/products/infrared-emitters/tof-evaluation-kit The ...
0
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1answer
49 views

What happens if a resistor or LED if it breaks in a circuit in regards to design C and B [closed]

In general, what happens to the overall current and the current and voltage going through each LED if a resistor or LED breaks in a configuration C and B? Assuming that the voltage source is constant, ...
2
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3answers
78 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
votes
1answer
48 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
votes
3answers
850 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
57 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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2answers
88 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 ...
0
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3answers
138 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 ...
0
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1answer
71 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
38 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 ...
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0answers
31 views

ws2811 pnp driver [duplicate]

I am going to drive 9 RGB leds with a WS2811 LED Driver and NPN transistor as a switch. Can you please check my schematic for mistakes or advice?
0
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1answer
86 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
52 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 -> ...
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0answers
22 views

Led mr16 downlights flickering [closed]

I have previous transformer with sec output: 700mA (const). 8.6 - 13VDC. Max 23V. Ta 50. Tc 80. I change the secondary output cable with MR16 cable and use it with philips classic led mr16 5.5 W. ...
0
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1answer
60 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 ...
0
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1answer
76 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
96 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
votes
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 ...
1
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2answers
32 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 ...
0
votes
2answers
48 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
votes
1answer
54 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
vote
4answers
91 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 ...
1
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0answers
45 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
64 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 ...
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1answer
44 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 ...
0
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1answer
74 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 ...
0
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2answers
58 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 ...
0
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0answers
46 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 ...
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2answers
482 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 ...