Linked Questions

151
votes
4answers
72k views

How can I efficiently drive an LED?

I understand that I can not connect an LED directly to a battery because it will draw too much current. Thus, there must be something else in the circuit to limit the current. What options are there? ...
4
votes
5answers
8k views

Board layout help: 64-output Mux! (for possible use in 8x8x8 LED Cube)

So just for practice I decided to design a 64-output mux in Eagle, I figured if its good it could be useful in the future. I did not use auto-router. Here is the PCB: (Click to zoom in) To the ...
11
votes
3answers
4k views

Simple \$12V_{AC}\$ to \$12V_{DC}\$ Rectifier

I want to convert a \$12V_{AC}\$ power supply output to use \$12V_{DC}\$ to power some outdoor LEDs. The power supply as it stands will light the LEDs (with a slight flicker from the reverse ...
8
votes
3answers
4k views

Miniature Traffic Light with Raspberry Pi: Wiring many LEDs

Background: I am a Civil Engineer specialized in traffic control devices and I have a small hobby project to build a scale model traffic light system. I can manage and control the traffic light ...
1
vote
2answers
2k views

Current and power-on time in LED multiplexing

Supposing to multiplex a LED matrix, after a certain number of columns the LEDs power-on time becomes too low in order to ensure a good LEDs brightness so you need to increase the current in order to ...
3
votes
1answer
3k views

Getting LEDs brighter without drawing much more current

I am developing a bike light that runs off of a 3.7V Li-Ion battery. I am currently running 3*10mm Ultra Bright White LEDs (~25,000mcd each). They each draw 20mA. I am relatively happy with the ratio ...
0
votes
2answers
959 views

LED modulated @ high voltage -vs- constant @ low voltage

I'm experimenting with LEDs with Arduino and have a question. For example; I have one basic 20mA LED that runs constant at 3.3v. I have another LED with that I PWM with a low duty cycle (6%). I up the ...
0
votes
3answers
296 views

LED visibility calculation

I want to select LEDs for a specific application. My requirement is as stated - I have a beacon. this should be visible to a person at a distance of say 50feet. Smallest form factor as weight is a ...
2
votes
1answer
438 views

How to find linear LEDs (light power(mW) vs current)?

I'm looking to use an LED in a control application. (feedback via LED to photodiode.) I found a few questions that didn't fit. Adjustable linear led driver? Linear, not PWM. Light intensity and ...
0
votes
1answer
243 views

Keeping your LED cool with PWM

SO I need to use some 1W and 3W leds for the brightnes, but my application will not allow the start heat sink. I have come across a few articles talking about using PWM to drive LEDs Does pulsing an ...
0
votes
2answers
211 views

Efficient 1 watt Led circuit

I'm new to this forum and glad to be here! I'm building a 1 watt led circuit (planning to...) most of the circuits I found online, make a lot of heat and I wish I could find a better one to get bright ...