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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18 views

WS2811 Driving Multiple sets of Parallel RGB LED's [on hold]

I have a WS2811 chip and I am trying to drive 15 SMD5050 LED's in a configuration of 3x3 parallel, i.e. ...
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1answer
58 views

Is it possible to make a LED sinusoid flasher with no harmonics? [on hold]

I am trying to make a LED flasher that changes the intensity of a LED sinusoidally. The problem is I would like to eliminate the harmonics of the sine wave, i.e. I would like to obtain a pure sine ...
0
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0answers
28 views

beer pong cup sensing pod IR RGB led using arduino [on hold]

I want to build a beer pong table that has LEDs. I need some help in building the RGB pods, so that when a cup is on the pod, it changes to green and when the cup is out it turns red. How should I ...
0
votes
1answer
59 views

High power LED vs. standard LED

How do high power LEDs with forward current of 350mA compare to bright 5mm LEDs with forward current of 20mA? If forward voltage is the same (same color) does that mean light output of 17.5 of 5mm ...
4
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4answers
1k views

LED lamps keep glowing when dimmer is turned off

For starters, I am not electrically capable, so bear with me. But, I did read similar questions that did not address, as far as I could tell, what I see happening (they may have, but I was too ...
0
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1answer
53 views

Can you explain how the following garden solar light circuit works?

I found the following circuit in a solar garden light. The cut off white and black wires are from the solar panel. What does the 4 pin transistor do?
0
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2answers
60 views

How to power 12V fan and 3V LED with a 9V battery?

I am trying to power a 12V fan and a 3V LED with a 9V battery, but I do not know where to begin. I want the light to automatically be lit up when the 9V battery is connected to clip but the fan will ...
0
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3answers
67 views

decrease 32V 3A DC voltage to 28V 3A

I am now building a power supply for a 100W LED light. Right now I already got 32V DC from my DIY Power Supply, with 3A current. I try to enable my PS to dim the light by regulate the voltage to the ...
0
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0answers
22 views

Using ws2811 led strip with led controller [on hold]

Im a novice :) and im tring to connect ws2811-48led-5meter led strip to rf6803 controller. The controller has 4 wires out :+,-,c,d and the led strip has 3 wires in : +,-,d The strip has also two ...
0
votes
1answer
57 views

What kind of IC can control touch sense and dimming? [on hold]

These little USB lights have a SOIC8 IC that controls the touch sense and dimming of the LEDs. I can't for the life of me find a similar IC. Does anyone know if an IC with the sole purpose of ...
1
vote
2answers
66 views

Register LED blink without reference to ground

I'm trying to trigger an Arduino pin based solely on the voltage across a blinking LED. I.e., when the LED blinks, I want to register the blink with the Arduino input pin. Unfortunately, I only have ...
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votes
2answers
91 views

Cumulative LEDs

For a better explanation let's think something like an equalizer bar Think one of these bars. The coloumn has 16levels from bottom to top. If the level 10's led need to light up then, the all levels ...
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1answer
73 views

lighting an led from inconsist voltage

I have a heated hose that uses 16-20 volts per 50'section, with a total of 400' (4 hoses). each section pulls about 10 amps. Each sections uses #6 AWG connectors and is feed from a multi tap ...
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votes
1answer
87 views

I want to create a custom LED segment display. What do I need to study? [on hold]

I want to create and then order a small run of a customized mass-produced LED segment displays for an art project. They will use PWM. It is not much more complex or detailed than a 7 or 16-segment ...
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votes
2answers
60 views

How to get an 8x8 led matrix pin out? [on hold]

I recently bought an 8x8 led array/matrix. I thought all the 8x8 led matrices had the same pinout, but I've found different pinouts. My 8x8 is not for Arduino.
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2answers
64 views

Detect EMF with an LED circuit?

So I am wanting to make a circuit that can detect an electromagnetic field and light up an LED to indicate that there is one present. I have seen circuits that output a sound when an EMF is detected ...
0
votes
0answers
10 views

Looking for a driver for the new Cree CXB1520 - Will a LMD400 work?

Not sure what's recommended as no one has updated their documentation. The 400 driver is the only one that reaches 40w as apposed to their 15w lmd300. I'll probably want to put a 36v regulator on the ...
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0answers
41 views

Commercial 1.5m / 5' LED light fitting parallel LED arrangement

I am reviewing LED light fittings for an industrial premises refit. As with most of the experienced users on this site I like to understand what I'm purchasing and have opened up a sample fitting to ...
0
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0answers
33 views

Can an IR transistor switch on a high speed object? [closed]

I am experimenting with different means of capturing motion. Would an IR transistor opposite an IR LED, be capable of switching in observance of some object moving upwards of 1500ft/sec? If this is ...
0
votes
1answer
58 views

What Type Of Switch Is only on for a second [duplicate]

I am looking for what type of switch is only only for a split second (1 second max) even when held. Basically: Press and hold button-->LED only on for a split second and back off even though I am ...
0
votes
1answer
47 views

LED driver circuit with both analog and pwm control

I would like to design an LED driver circuit that allows for simultaneous analog and pwm control. That is, I would like to set the the LED current using an analog signal and then be able to switch ...
0
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0answers
22 views

RC Relaxation Oscillator Problems

I found a schematic for this oscillator online here and I tried it, but instead of the LED turning on and off sawtooth style, it got brighter slowly, and stayed bright without getting dimmer. What is ...
0
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1answer
40 views

Formula for LED refresh rate?

Suppose I have a line of N LED's, of which only one is on at a time. Is there a formula relating N to the minimum speed at ...
4
votes
1answer
56 views

Parallel LEDs in CoB-like array

I understand the problems with parallel LEDs sharing a current source. However, I came acrosse this LED from Cree, which, in one configuration described in the datasheet, has its internal LEDs ...
0
votes
4answers
105 views

Large parallel strings of LEDs

I want to drive multiple strings of XTE LEDs (total of ~36 LEDs). The relevent (-ish) specs are as follows: I_f,max = 1.5 A Desired I_f = 0.5 A V_f = 2.94 V (0.5A @ 85C) According to some ...
2
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0answers
63 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 ...
0
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2answers
32 views

constant current source circuit 1550e

I am trying to design current source of 20mA for LED 1550e(thorlabs).The circuit designed gives accurate result in proteus simulation that LED is giving a voltage drop of around 1.2V and drawing 20mA ...
0
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0answers
39 views

3*3*3 LED Cube using 555 timer and 4020

Hello everyone I am new to electronics and I am building a LED cube for my class project. The circuit i built was the one i found online and I got it working but i want to add a n-channel mosfet to ...
0
votes
1answer
45 views

Safety considerations when using LED and a comparator

I want to make a simple circuit, it uses two comparators to drive two LEDs, it should turn the LED (green) if the voltage is higher than let's say +2.5V. If is lower then turn the first one off and on ...
0
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1answer
40 views

Control USB powered light with PWM, would it work?

A few weeks ago, I asked about controlling a DC powered LED lamp using PWM here, I was told that if I can get a LED lamp that uses an external DC adapter to power up, I can use a MOSFET and control it ...
0
votes
1answer
36 views

What is optical bandwidth and electrical bandwidth

I was reading a book about Optical Wireless Communication. In the chapter where the transmitters are explained, there is a figure showing two types of bandwidth for LEDs. This confused me a bit, ...
0
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0answers
38 views

IR LED output linearity with current?

I am thinking of running an IR LED at very low current (<10uA). Is light output linear with current when current drops to that extent?
2
votes
1answer
126 views

How can I stop the flicker of LEDs?

Recently I started messing around with controlling RGB leds with the Arduino for a project I'm building, so I built the following schematic: simulate this circuit – Schematic created ...
0
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1answer
48 views

Current Limiting Resistors for Multi-Branch LED circuit

I have bought some of the following LEDs (going to try either for brightness/size): 100 Pcs 0603 SMD Superbright LED Yellow Light Emitting Diodes 40 Pcs SMD 1206 LED Lamp Yellow Light Emitting ...
0
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1answer
40 views

analog shut down whilst turning on an LED

I am a EE student from Denmark, in the middle of making a class D audio amplifier. In this matter, I have stumpled across a needed circuitry. I need a way to shut off my gate driver (essentially the ...
0
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0answers
65 views

How to connect these two led strings?

I've recently bought myself 2 sets of leds. Each set has 10 leds in a row powered by a solar panel which charges 2x 1.2V batteries. My question is what do I have to do when I want to have all of the ...
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2answers
79 views

LED Circuit- Beginner seeks help

I am a beginner in electronics and circuits and I decided to make my first circuit. It is an arrangement that spells SPEC with 5mm LED lights. I familiarised myself with the basic concepts (Voltage, ...
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votes
1answer
47 views

VHDL blink leds for changing bits in vector signal

Suppose there's two SDT_LOGIC_VECTOR signals A_READ and A_OUT, both 8 bits wide. A_READ is updated by some process at random intervals. A_OUT is connected to 8 LED's. I want to blink a LED for each ...
0
votes
1answer
120 views

How to increase voltage drop across LED? [closed]

Hi I am using LED of 1550nm(Datasheet Link Attached) thorlabs.and voltage drop which I am getting across it is 0.866V. I have connected a 60ohm resistor in series and voltage which I've provided is ...
5
votes
2answers
984 views

Where is this LED getting its timing from? [duplicate]

So this little board when connected to 5v and GND start blinking different colors in different orders and with different timing for colors to stay on! There is nothing on the board other than the LED ...
0
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1answer
59 views

Slowly dimming LED-s

I was wondering if it is possible to make LED-s in an astable multivibrator slowly get brighter then slowly dimmer. Can somebody help me please? Thank you for your kindness! Have a good day!
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votes
2answers
156 views

Why do we use resistor along with the transistor?

from the knowledge i have, i know that a transistor is a special kind of resistor that can change it's resistance depending on the input at it's base. questions sorry for the big picture => Why do ...
0
votes
2answers
75 views

Designing a open drain LED driver

Will this open drain LED driver circuit work ? The open drain IO is governed by the following equation 0.5 <= V_LED_OUT <= 3.6 V (abs_max) V_LED_OUT is the voltage from open drain IO pin to ...
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votes
2answers
65 views

Can I use this to power my 10w LED?

http://www.ebay.com/itm/181888372572?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT I need to power a 10w(12v900ma) led using a 12v sla, can I power the LED using this 600w booster ? ...
0
votes
0answers
42 views

Table lamp CE marking / safety testing for sale to the public

I am designing a table lamp that uses the following components: An LED coin module (running at 3.15 watts, 8.4 to 9.75 volts) powered by a plug-in constant current LED driver that is CE marked I am ...
-1
votes
1answer
54 views

Gas Leakage Circuit [closed]

What Transistor should i use instead of SL100? thanks
0
votes
1answer
61 views

(Design) Resistor on anode or cathode? [duplicate]

I was recently confused on where the resistor would go on the circuit. I then learned that it didn't matter. Is there a standardized sequence for the placement of resistors? For example, battery -> ...
0
votes
1answer
46 views

What is the interface that connects the TV LED screen to the PCB

WHile this may be a rather open question, I see that most TV's expose a HDMI port. The HDMI port connects to something that runs linux which in turn connects to the LED screen. What is the interface ...
0
votes
1answer
57 views

How to troubleshoot led panel

I wanted figure out what is wrong with my led setup. I have 78 leds in series connected to a mean well elg-150-c500b data sheet The leds are a few different colors they range vf 3.6v to 3.8v and max ...
0
votes
2answers
95 views

Efficient way of driving 10w LED with a 12v SLA battery?

I have a 12v SLA battery from an old UPS and two 10w led. I'm new to these stuff. I connected one LED directly to the battery and in about 15mins it go hot and now one row doesn't work. I didn't ...