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
45 views
Inverting a push button
I have a push button that by default is in 'ON' state and a LED attached to it. I want the LED to light up when the button is pushed down, instead of being on by default.
As far as I understood I ...
-5
votes
1answer
45 views
right way to connect leds?
I have connected 5 3W leds in series to 12V power supply.
Measured LED current is ~300mA.
Is there possible to connect 4 led's and make them drain ~700mA ?
I tried to connect 4 leds but one of them ...
3
votes
2answers
392 views
Single LED powered directly from AC mains
Today I disassembled a power strip (power extension) and found a LED connected directly to AC with a normal resistor (not a power resistor). How is it working as I thought it would be burned in no ...
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0answers
33 views
LED's: How to mimic color temperature of Sunlight using LED's [on hold]
I want to build a LED light which produces the colour of sunlight. I wish to mimic the colour temperature of sunlight during sunrise & sunset & even during bright daylight conditions. I am ...
0
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0answers
23 views
LED light bulb flickering in socket, incandescent works fine [migrated]
I have a couple of outdoor light sockets with built in motion detectors. These seem to work as you'd expect with regular incandescent bulbs- you can set a timer for how long you want them to be on ...
0
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0answers
30 views
Is it possible to replace the white LED illumination on a Canon 9000F Mark II flatbed scanner to a red LED?
I have recently bought a flatbed scanner, Canon 9000F Mark II, to be used for performing densitometry on SDS-PAGE electrophoresis gels, stained with Commassie Blue.
Whereas the narrow spectral width ...
0
votes
2answers
22 views
Prevent Exceeding of Potentiometer Power Rating
I am using a 10k digital potentiometer to adjust the brightness of an LED.
However, I need to make sure that when I reduce the resistance on the pot, it will not exceed the maximum power ratings.
The ...
1
vote
2answers
63 views
LED filament bulb driver
I need to design a constant current driver for a filament LED bulb. The input is 230VAC and the output should be 120VDC, 20mA (constant current) for 4 filaments arranged in series-parallel structure. ...
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0answers
25 views
LED pulses with constant current driver
I am trying to drive two Nichia LEDs, the NC4W rated at 13.6V/1A. My supply is either a pack of 4 18650 cells in series (16V) or a DC DC boost converter rated at least at 100W. I tried a couple of ...
1
vote
1answer
54 views
Ease of use of SMD Led components
I was thinking about inserting some lights in postcards. But classic leds would increase the thickness too much.
Is it easy enough to use this kind of component for a simple circuit(just one or two ...
-3
votes
0answers
62 views
How to wire 16 LEDs together [on hold]
I'm trying to wire 16 white LEDs together, used a 9v battery but it overheated and melted the wires connecting the battery to the LEDs. The LEDs were bought from eBay and are all pre-wired. Any ...
0
votes
1answer
78 views
Why won't the LED illuminate this way?
Attached a 9vdc motor to an LED to simulate a simple "generator" and I can get it to illuminate by swiftly spinning the motor in quick bursts, but if I connect a drill to the motor so there's a ...
4
votes
5answers
263 views
IRF3205 MOSFET gate threshold voltage higher than expected
I have been trying to drive a 12 V LED array with an IRF3205 MOSFET.
I wanted to do this:
simulate this circuit – Schematic created using CircuitLab
However, when I tested it, the ...
0
votes
0answers
29 views
Troubleshooting LED strip lighting [on hold]
I purchased some led strip lighting from Costco a few years ago.
It was basically 6 tubes w/ 6 LEDs in each tube. The tubes are designed to connect together and plug into a power module that is ...
-5
votes
1answer
61 views
raspberry pi, fastest way to blink with a lot of leds? [on hold]
I saw this technology:
kino-mo
In short words they placed leds onto a usual fan.
I tried to do the same thing but I can't just take a strip of leds with ws2812 and blink with them - they are too ...
-3
votes
2answers
72 views
Drop voltage in wire [on hold]
Hi I have hup swich that have converter 5 v 600 mamp in length wire 30 meter it work and shut off but I bring converter 1000 mamp and it work good ,what the drop or lost power ? By the way in utp cat ...
0
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0answers
42 views
why 18650 won't light up multiple LED lights?
My project consists of illuminating 25-35 Led lights with a 18650 battery. Sounds like it should be simple. Until I tried. I hooked up in parallel 30 5mm LED lights. I installed a 120ohm resistor to a ...
0
votes
1answer
46 views
Triggering a LED and interrupting it quickly (with a PIR sensor). What do I need for this?
I'm an artist working on a interactive installation. I'm a beginner in electronics and I'm feeling a little bit lost here, can you help me?
I have a 5v circuit with a PIR sensor activating a LED and ...
0
votes
2answers
44 views
Can I use a USB connector/plug for RGB Led Strip
So I have an RGB Led Strip that requires power (3 Colours and the ground).
In total it draws about 1A @ 12V = 12W.
Could a USB socket be used to handle this? Otherwise I'm simply seeking a neat and ...
0
votes
2answers
39 views
Dimmable AC LED controlled by Arduino
I am a beginner, and I have a school project that requires me to use Arduino or any other microcontroller to control an LED light.
After some research, I found out that not all LEDs support dimming, ...
-3
votes
3answers
68 views
series leds powered with a 6v 4.5ah battery [closed]
I'm running 48 leds with a 6v 4.5AH lead acid battery, there are 24 leds connected in parallel each parellel line has got 2 leds making them 48 leds. the leds are standard 5mm 25cd white leds with ...
1
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4answers
602 views
Side LED - Orientation wrong
I am using one of these Side LED's on the edge of a PCB to illuminate it through the light guide.
...
-3
votes
1answer
93 views
How do I build a Circut to create temperature changes in LEDs? Looking for a range of 3000 to 6,000 for photography? [closed]
I see commercial lights for photography that can change color in the range of 3-6,000 or tungsten to daylight values. These are not arrays of three RGB lights but rather single LEDs and the ...
20
votes
3answers
1k views
What's the purpose of traces that are later punched out?
I've found this odd feature on an FPC in a Camera than handles button and switch input.
You can see there are traces that look like they were once connected and later punched out to be cut. The one ...
-2
votes
2answers
66 views
Choosing resistance in series with a photoresistor for best light-measurement resolution
simulate this circuit – Schematic created using CircuitLab
I have a photoresistor, R1, and as a voltage divider a fixed resistance, R2. There is a voltage of 5V over these two, and the ...
0
votes
0answers
41 views
Is a 120V smd5050 led strip really 120 volts? [closed]
There are many SMD5050-based LED light strips that are referred-to as being "120 volt". But is the strip itself 120V, or is the "AC power cord" that's typically sold with the strips actually ...
0
votes
1answer
41 views
Powering 5v LEDs with 6 or 12 volt batteries
I'm building an art piece that uses about 2000 RGB LEDs. They are WS 2812b LEDs, and I expect the normal draw to be around 200-300 watts. If all bulbs go full white at the same time, it could pull up ...
2
votes
2answers
81 views
Is this an RC filter in the circuit for a nightlight?
So there is this nightlight (a little flower that you plug in directly into a mains socket and switching it on gives you some light to light up your bedroom at night) which I dismantled and tried to ...
5
votes
3answers
889 views
Is the wavelength of the light emitted from an LED at its turn-on voltage greater than or less than the peak wavelength of the LED?
Ok, so I know that the intensity of the light given by an LED is the minimum it can be at the turn-on voltage, however I don't know if the wavelength of the light emitted from the LED at the turn-on ...
0
votes
0answers
31 views
Switch a current controlled LED by a MOSFET
I have an array of LEDs. All LEDs are different and take current from 700 to 1000mA. Forward voltage drop is 0.3 to 6V. They share a common ground.
I want to select only one LED at a time by a 0-5V ...
0
votes
2answers
49 views
LED's with switch on a 12v supply
I hope there is someone who will assist me with this.
I have 5 LEDs, with a switch in front of them. I use a 12v supply.
Switches can be randomly turned on or off. LED's are 2v, 10 mA.
I can not get ...
4
votes
2answers
409 views
Visible Light Communication LED Turnoff Time Problem [closed]
I am doing Project on Wireless Optical Communication(Visible Light Communication). I am using Nicha NSPW510 DS White LED at transmitter and Vishay BPW34 PIN photodiode at receiver. The problem is ...
0
votes
1answer
63 views
LED forward voltage - why does series resistor take excess voltage?
I am currently having a problem wrapping my head around a pretty simple problem.
I know in multiple sources when taking into account considerations and assumptions of powering an LED you can use it's ...
0
votes
3answers
66 views
Burned out potentiometer
DISCLAIMER: I am just tinkering with electrical engineering and can barely do the basics yet.
Background
I have done a little work on a breadboard connected to my Raspberry Pi, but today I wanted to ...
0
votes
3answers
108 views
Can I somehow use one PWM output to set various LEDs to different brightness?
I would like to build a project in which 15 groups of LEDs are set to a brightness level. I have an Arduino with digital PWM outputs (which can mimic a range of voltages.) How can I do this?
One ...
0
votes
0answers
62 views
12v 3amp device powered via 9amp molex output from psu - will device only draw amps required? [duplicate]
I have a problem with a 12v lcd controller not switching on, even though the red LED is indicating power.
I'm connecting it via a "molex connector output" from a standard PC psu, although the molex ...
1
vote
0answers
62 views
Ultra low ripple constant-current LED driver design
I designed a LED driver(SMPS configuration) with ILD6150XUMA1 and below is the circuit. I used it with AC/DC adapter. The thing is, th optical system is ultra sensitive and ripple from the LED ...
-1
votes
1answer
46 views
will this system work? hi power led
Well doing this for my fish tank and i need some tips and advise.
The idea is to use laptop charger for power. 19v 4.7amp 90w.
Will use 25 leds that operates at 3.7v and 700mah and parallel em doing ...
0
votes
0answers
19 views
Help with driving rgb leds with modded PC case (hdd activity, pwr buttons, led strip)
I have a custom home pc / server mini itx case (2 computers in one case), which is still project in progress. I have created individual hard drive activity leds via this circuit and it's been working ...
1
vote
1answer
69 views
PWM or Variable Resistor [closed]
For a school project, I have to design and perform an experiment of my choice. I have chosen to test the efficiency of variable resistors and PWM circuits by testing the amount of energy wasted (heat ...
0
votes
2answers
68 views
Switching on and off a LED light if a AC is passing through a wire or not
This is the basic setup of what I'm going to do. Have a wire plugged into the mains that is then connected to a ON/OFF flip switch then goes on to the rest of my project. Want I want to do is to add ...
0
votes
3answers
61 views
How to drive an LED with an LED driver
I found BCR421 driver and want to ask how to properly drive TSSF4500 LED. All the parameters seem to make sense if look separately, but where do I start to determine the necessary parameters?
It ...
0
votes
1answer
33 views
Calculate current with potentiometer
I've built a circuit on a breadboard using a 10K potentiometer, a 220 ohm resistor and a LED. They are connected in series. Using Ohm's law, you find that:
Total resistance \$R = 10000 + 220 = ...
-1
votes
0answers
27 views
How to drive 4 different colored high power 3W LEDs from a 4 cell LiPo?
I'm building a quadcopter and want to equip it with 4 (2 red, 2 green) high power 3W LEDs.
Now I sadly don't know too much about electrical engineering now, but I want to learn.
Now my question is, ...
3
votes
1answer
103 views
Different LED for POWER ON and for LOAD ON, how to wire?
As you can see in the picture, for LED1 it's all good, 12v and 800 ohms = 15 mA to the led.
But i don't know how to wire LED2 since the load to the LED will change depending on the load/Vout of ...
0
votes
0answers
50 views
Why has my constant current driver no voltage output?
I am trying to build a lamp from a 300mA/max. 20V constant current driver (the one left over from here) and two 350mA, 15-17V white LEDs. When I do not connect anything to the driver, I can measure ...
11
votes
2answers
3k views
Does a DC toy motor emit AC when you spin it?
I just watched a video on Facebook by somebody who built a project to run an LED using a 9 volt DC motor scrounged from a battery operated toy. They simply wired the LED to the motor and then used a ...
0
votes
0answers
60 views
PWM + Strobe Light using Arduino on 100W LED?
I want to create something like the Sunblaster by DIY Perks, but I want to include a PWM regulation and a strobe function using an Arduino.
I want to use this boost converter to drive a 100W LED. I ...
0
votes
0answers
33 views
analog sensor on Beaglebone Black that generates voltage
As I look at the sensors that people recommend for the Beaglebone Black, they mostly seem to recommend resistive sensors--photoresistors and the like. Connect it to the 1.8V source and an analog in ...
0
votes
1answer
51 views
2 Blue LEDS , in series or parallel/ optimal power resistor type of batteries compact area
I intend on making a project illuminating an acrylic transparent rod. drill holes on both sides and inserting Blue LEDS tight space wired in series or parallel what resistor value and perhaps small ...
