All Questions
Tagged with current-limiting led
60
questions
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
0
votes
0
answers
53
views
TPS2553 Current limiting [closed]
Editing this so it can be deleted for double post reasons.
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 ~...
- 31
0
votes
0
answers
67
views
LEDs without resistors in parallel circuit
I have connected 75 WS2812B LEDs in parallel circuit as shown in manufacturer's datasheet:
Source: https://www.tme.eu/Document/64e8d425b90f84990264129a9679149c/WS2812B-V5.pdf
Since all LEDs should ...
- 131
0
votes
1
answer
70
views
50 watt high-power LED current problem [duplicate]
I am using this 50 watt high power LED:
.
And want to power it using this voltage booster:
From 12 V to 34 V as the requirements of the LED datasheet.
Will it work?
I read that I need to limit the ...
0
votes
2
answers
867
views
Calculating current limiting resistor for high current circuits
I am designing a simple three-phase inverter to begin working in power electronics. I have no experience in power electronics and minor experience designing circuits. While working on it, I ...
- 117
1
vote
1
answer
551
views
Efficient and cost-effective way to limit current across an LED strip
I am currently attempting to build a DIY driver board to power the backlight of an LM270WQ1 panel.
Per the datasheet, there are six LED strips, each of which take 36V @ 350mA.
The adapter board that ...
0
votes
2
answers
166
views
Why is my BJT current control circuit not controlling current?
I have built this circuit (except the Re I bought came out to Re = 0.21 ohms after measuring it, so I used Rin = 680 ohms and R1 = 18k) to control current through eight of these LEDs using this BJT.
...
- 43
0
votes
1
answer
86
views
How to limit power to LED, efficiently
I am looking to use a 12V, 5 ampere car battery on a small 5V, 2A LED. Typical applications online use a resistor or voltage regulator, but since I am using a battery I would like to conserve power, ...
- 239
-1
votes
2
answers
131
views
Led strip and relay current splitting?
I have a 12 V LED strip that works at 10 W. I want it to run at multiple current configurations with two relays and without the help of a microcontroller. I am attaching a diagram of my intended setup....
- 690
1
vote
1
answer
68
views
LED strip light power
I am looking at using small lengths of single colour 12v LED strip (2835) in a project, maybe just 1 or two sections i.e. 3 or 6 LED's. I have tried single 2 pin LED's and they aren't bright enough.
...
- 11
0
votes
3
answers
839
views
How can I figure out what the forward current and forward voltage will be for an LED given a resistor size
We're trying to order some boards from our PCBA manufacturer but they're having trouble sourcing our original LEDs (QBLP601-IW). They proposed an alternative LED (LSM0603443V) and I'm trying to be ...
- 626
0
votes
3
answers
374
views
Current limiting or voltage dropping [duplicate]
I was trying to understand the usage for the word "current limiting resistor." Taking an example of a simple LED with a resistor in series, the way I understand this is we are trying to ...
- 1
0
votes
2
answers
360
views
Safe to use series resistors for powering common anode RGB LED from single constant current source?
I have a 3-9W common anode RGB LED (https://cdn-shop.adafruit.com/product-files/2524/FD-9RGB-Y2.pdf) and want to vary each leg's voltage with PWM through FETs, namely IRLZ44Ns, and an Arduino, in a ...
- 17
-2
votes
5
answers
2k
views
Why can't we light up 4x 3V leds with a 12V power supply?
To calculate the resistor to limit the current, if we use R=P/I² formula, it gives us wrong parameters rather than using V=RxI, so the 12V-12V is 0 and the P formula gives us nothing.
Why is it so?
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 ...
1
vote
3
answers
2k
views
Hi! I would like to connect my LED lights (Vaxmyra from IKEA) designed for 24V system into my 12V system, do I need a current limiting resistor?
I bought these VAXMYRA LEDs thinking they were made for 12V but apparently they need to be feeded 24V.
Supposedly I'll have to install a 24V DC step-up converter, but this device can deliver up to 3A ...
3
votes
2
answers
601
views
LED fairy lights with series capacitor?
I've opened up the battery box of a string of fairy lights (like pictured at bottom) and found a resistor, plus what looks like a capacitor in series with the lights. Is this really a capacitor? If so,...
- 255
0
votes
0
answers
28
views
LED circiuit for a current limited circuit
I have the following requirements for a circuit:
The circuit is supplied from a 500mA current limited voltage source
The circuit should indicate the status of the supply, i.e. if it is in current ...
- 125
0
votes
1
answer
337
views
Limiting the Current of a Constant Current LED Driver which is Driving a Halogen Bulb
I am powering a 12V, 35W halogen bulb with a MeanWell HLG-100H-20B constant current power supply. The "B" version of this power supply has a really neat dimming control system which lets one control ...
-2
votes
1
answer
107
views
Do I have to use current limiting resistor for LED in this configuration?
LM741 datasheet says that it can output a maximum of 20-25 mA. So in this case, is that R5 a must, or will it be safe not using it?
Assuming LEDs can withstand 25mA.
- 2,106
0
votes
2
answers
59
views
Reducing current in a circuit without reducing voltage [duplicate]
I didn't find a solution in the other similar posts or maybe I don't understand them.
Here is my problem : I've got power supply with an output of 5V and 8A to feed 128 leds drawing 5V and 50mA each. ...
3
votes
1
answer
768
views
Why are these LED current limiting resistors so big?
I'm looking at the charging circuit for a lithium ion battery that was made by Adafruit. Here's an excerpt:
If there's a 5V rail from the USB port and a 470 Ohms resistor, is that limiting the ...
- 626
1
vote
2
answers
257
views
High power LED array
I’m designing SLA 3D printer and I need to design UV LED array for LCD screen backlight. Preliminary design is 5x3 (5 parallel lines with three LEDs in each). All LEDs will be soldered on PCB.
The ...
- 53
1
vote
1
answer
1k
views
4 channel optocoupler [duplicate]
I was designing a dual H bridge board which uses some logic signals to drive 8 mosfets. Initially I was using 8 optocouplers per board which was really annoying to wire up. after a bit of searching, I ...
- 347
0
votes
1
answer
117
views
How to measure and power an array of unknown RGB LEDs?
I have 5 of these plastic moldings that each have 2 RGB LEDs inside along with a microcontroller that rotates through the color spectrum for aesthetics. I want to bypass the microcontroller so that I ...
- 105
1
vote
4
answers
1k
views
Why my hex inverter chips (all three of them) are not producing a HIGH output with low input?
I wont say I am great at reading datasheets, but I noticed that for 74LS06 chip, Ioh is 0.25 mA and Iol is 40mA. Does that mean it can light-up an LED when its output is low but not when its output is ...
- 120
0
votes
3
answers
849
views
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
1
vote
2
answers
1k
views
Overcurrent Protection for COB Leds wired in parallel powered by Const Voltage Mean Well Driver
Roughly this is my current wiring diagram.
The Mean Well driver that I am using is the HLG-185H-36B. Output 36v DC, max current 5.2A. The Cobs are 36V and have a max operating current of 2.76A, ...
- 11
1
vote
3
answers
2k
views
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
3
votes
3
answers
2k
views
Current limiting from a USB supply
I am designing a device which must power a number of RGB LEDs. I am currently looking at WS2812 "NeoPixel" style LEDs, which have a max current draw of 60mA each. I would like to have a large number ...
- 133