All Questions
Tagged with current-limiting led
9
questions
42
votes
2
answers
22k
views
Correct formula for LED current-limiting resistor?
I'm trying to work out what value resistor to use in a LED circuit. The equation I'd use to do this is:
$$ R = \frac{V_{cc} - V_f}{I_f} $$
Seems logical, and makes complete sense. The answers to the ...
- 1,092
3
votes
2
answers
773
views
What's the difference of placing multiple resistors and one resistor for limiting the current of LEDs?
I'm looking at a diagram and wondering if I could use just one resistor to limit the current of the LEDs instead of multiple resistors so that the cathodes are all connected to the same resistor.
JL
- 51
10
votes
4
answers
11k
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Why is LED lighting up despite Supply voltage < Forward voltage
I have an LED which has specified Typical forward voltage of 3.5V and Maximum forward voltage 3.9V.
I applied 3.3V across it with a 300 Ohm resistor in series. Why did it light up?
I am wondering if ...
- 4,942
5
votes
3
answers
2k
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Do I need a current limiting resistor when powering an LED below its forward voltage?
I've reviewed the questions:
Why can you use an LED below voltage?
Is a current-limiting resistor required for LEDs if the forward voltage and supply voltage are equal?
But combining them begs ...
- 34.3k
3
votes
2
answers
102
views
Boosting load current of voltage regulator
I'm trying to connect little 3v LEDs to a motorcycle's alternator and i want to regulate the voltage of it to 3 volts so the LEDs don't burn up
the alternator gives off 2.5 volts and over with 3 amps ...
2
votes
2
answers
113
views
TPS2553 Current limiting for RGB LEDs
I'm building a keyboard which will use SK6803 mini-e LEDs (ws2812 driver). I'm using a Pi Pico and as such the USB limit for current draw is ~500mA. I'm looking to limit the current draw from the LEDs ...
- 31
1
vote
3
answers
2k
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Switching circuit for driving LED at different current values
simulate this circuit – Schematic created using CircuitLab
Above schematic is for limiting current to 4A when battery is connected to LEDs.
Datasheet of LED(BXRA-56C5300H 50W) are 23.5 Vf and 2....
- 9
0
votes
3
answers
849
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How to solve for current given resistor value for LED circuit?
So I have the following LED circuit:
I know how to find the forward voltage and current from the datasheet of the LED and how to then solve for the appropriate value of \$R\$.
However, what I really ...
- 171
0
votes
4
answers
3k
views
How to get a constant current from a DC power supply for high voltage/current
For a project we're working on we require 4 high power LEDs, we've been using these: http://www.digikey.ca/product-detail/en/bridgelux/BXRC-50C10K0-L-24/976-1277-ND/5180249.
We've purchased this ...
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