All Questions
Tagged with current-limiting led
60
questions
0
votes
4
answers
3k
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SMD LED for microprocessor output without resistor [closed]
I have a very simple problem to solve and I'm surprised there is no common solution for it.
I need to connect several indicator LEDs to microprocessor outputs and I know I need a serial current-...
- 117
0
votes
2
answers
193
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Effects of current/voltage limiting of LEDs
First of all, I have read many articles about the non-linear effects of voltage vs current of LEDs. I also know that current will rise as temperature rises, batteries have resistance, LEDs brightness ...
- 43
1
vote
2
answers
1k
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LED indicators for HVAC (24 VAC)
I have an HVAC which I would like to add some status indicators to. I have some tri color LEDs, but could use suggestions as to how to utilize those LEDs.
What I am figuring is that I need a diode ...
- 149
0
votes
1
answer
475
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Ned help modifying a Harbor Freight LED flashlight into a light source for a microscope
I have a couple of Harbor Freight free-when-you-buy-something-else flashlights.
I want to modify one of them into a light source for a microscope. I've taken (10) of the (24) white LEDs off of one ...
7
votes
2
answers
701
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Current limiting resistors
I notice that in Ben Eater's project for the 74 series logic chip computer, which my son and I are building, sometimes he uses current limiting resistors on LEDs on the pins of some chips, and on ...
- 193
5
votes
5
answers
878
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Dynamically dimming individual LEDs in a lighting system [duplicate]
I'm planning to build an aquarium lightning system with individually controllable LED's, I don't have much experience with electronics except from the irregular tinkering, but I'm a programmer and I ...
- 158
0
votes
1
answer
121
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Why is the current wrong after resistors in series with simple LED?
Setup
source --- 1.5V batteries x2 = 3V
LED --- 2V 35mA http://www.futurlec.com/LED/LED5R.shtml
Resistors --- CR1W 1W 10ohm +-5% x 4 = 40ohm
Description
I have your average "Light up a LED" ...
- 3
0
votes
1
answer
1k
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Calculating LED current using ohms law
I've got a 4 digit green 7 segment display (technically 5, it's from a microwave and the "5th" digit is the function lights on the top and bottom). I don't have a datasheet for it. It's common cathode,...
- 347
0
votes
1
answer
301
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Common current limit resistor for multiple LEDs?
First, I realize the "common resistor for multiple LEDs" question has been asked. However, I have a different case where the LEDS are FET driven and reverse logic.
I have the following circuit. The ...
- 163
0
votes
4
answers
3k
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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 ...
- 1
1
vote
4
answers
835
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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 ...
0
votes
1
answer
445
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 Diodes
...
- 105
4
votes
5
answers
10k
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How to limit current to LEDs
I have understood that this is a bad way to do it:
Since some LED can draw more current than others.
So lets say I would power some high powered LEDs, like say 10 x 3W LED with a DC forward voltage ...
- 697
0
votes
1
answer
453
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Cascading WS2803 LED drivers, each with different output current
I've decided on using WS2803 PWM constant current LED drivers. I'd like to cascade two of them and use the first one for 15mA output and the second one for 20mA output (each chip for driving different ...
0
votes
1
answer
127
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Voltages to keep my circuit running at 200mA with NMOSFETS
Im trying to build a circuit to send information using IR led, using pulse signals
my leds (TSAL6400) operates at 1.35V, and their maximum pulse current is rated 200mA
After struggling a bit with ...
- 227