High Power LED Tutorial #1 - How to Drive 1W and 3W LEDs from 12 Volts

High power LEDs differ from regular LEDs in a number of respects. Firstly, current regulation using resistors is impractical so it's necessary to use a switched mode voltage and current regulator. Secondly, they generate heat which must be drawn away from the LED to prevent damage by overheating.

[@albertomartinsen3357]

Julian, you are THE BEST explaining easily how to drive LEDs!! THANK YOU!!! I'm learning a lot with your videos!!

[@JulianIlett]

Alberto Martinsen Thanks Alberto

[@davidferguson8478]

Hi I have a 36 watt led driver can I use that with these leds ?

[@JulianIlett]

You're absolutely right, for prolonged use, the 1W LEDs should also be properly heatsinked, so buying them on the star boards is a good idea. Also I was using them in free air outdoors - if they're in some sort of enclosure, the heat build-up could be quite rapid.

[@kashubelua]

Went through full loud shooting apes in the internet jungle, started being desperately entangled in inextricable intellectual porridge, then sinking stuck in quicksand thought when i saw the regulated Led light....Tarzan julian saved me... Thank you a lot! that's one good tutorial.

[@JulianIlett]

No problem. In fact if you look through their products, you'll find a 1W LED driver with EN input (for PWM control) for $4.37 which seems pretty reasonable to me. It's got a "Make Offer" thing too, so you could probably get 10 units for quite a bit less than that.

[@B0M0A0K]

Outstanding video. I'm a beginner at all this but am currently trying to design a CREE XM-L T6 LED system for my motorbike, so this was exactly what I needed to see. Well done.

[@deveshtawre5459]

Was that efficient?

[@limroyston9773]

Hi Julian! Your videos are very brief and easy to absorb for any newbies or experts. Thanks and continue with the videos. BTW, those high power LEDs such as 20,30,50 and 100 Watts do come with the Drivers incorporated into the LED itself. So we save on power supplies and drivers but we pay a little bit more on the LEDs. Do put up a video on these new ones please! Bye!

[@JulianIlett]

Yes - that should be OK. Three LEDs in series will need about 10 volts, the buck regulator should be able to supply that from a 12v input, but you'll be near the limit with 2v difference between input and output. 2 rows (or columns depending how you look at it) will require twice the current of a single row - 2x 700mA is 1400mA. This should work.

[@kakilovag]

You skipped the part where you say you set the voltage to 3.3V for the single led setup. Other than that truly great video and explanation. Cheers!

[@davidallenhagins1988]

Awesome information! In the process of designing custom shaped turn signals and brake light for my motorcycle. So this helps immensely with the wiring issue.

[@johnturner9561]

Hi Julian I must say I really enjoy your videos,even ones that I have no interest in, I just enjoy the tech aspects that you explain in detail.I am starting a project in replacing my 4 ft. shop lights.I could buy the new led fixtures but I enjoy the diy aspect Here is what I have in mind, Am planning to use the Epistar LED Emitter: 3W - Output Lumens: 180-210 Lumens - DC Forward Voltage (VF) : 3.0-3.4Vdc - DC Forward Currect (IF) : 700mA - Color Temp: 6000~6500K ( White) - Beam Angle: 120 degrees mounted on a heat sink in parallel 8 leds per fixture for a total of 48 leds. The question I have is I have several old PC power supplies that I would like to use for power.I know that I will probably need voltage/current buck converter to regulate power, will one 300 watt supply work or do you have a better solution as this is my first led project Thanks

[@techcheck5019]

For step up you just need a step up converter (boost converter). They look very similar and are similar in price, they are perfect for wiring up a whole horde of LED's in series. You can turn 12v into 33v and run 10 LED's in series. I usually run each LED at around 3.3v, a bit under the 3.5v rating.

[@techcheck5019]

The output still depends on the input though, when the voltage deceases in a battery the buck converter wont be still putting out the same converted voltage, it will lower. And it's the same if the source voltage increased (like your example of the alternator). An LED can have the right current, but if the voltage is far too high the LED will still burn out as voltage times amperage = watt power. So you still run the risk of burning it out, this is precisely why LED's have voltage ratings to start with! You can't just feed them any voltage and make sure that just the current is fine. So if your battery went up to 14.4v and you set the buck converter before at 12.6v battery input to 3.5v output for LED's and 30mA. Then when the battery voltage goes up from the alternator the output will go past 3.5v (most likely past 4v). Which will lead to the LED not consuming it's normal 0.1w, but instead wthin 0.13-0.15w. So while it isn't terrible, usually it will shorten their life significantly to be running 50% more power through them than they are rated for.

[@richardsandwell2285]

A few words of caution, I have recently bought a current and voltage controlled circuit off E-bay, I wanted to push a constant 150 mA of current through 6 luxeon LEDs from a 12 volt DC battery supply, underdriving them by a long way and cooling them with oversized Aluminium heat sinks because I want them to last virtually forever. I carefully set up the circuit to limit current to 150 mA and the voltage was set well within limits. However, I made the fatal mistake of hooking up the power to the circuit and then connecting the LEDs to the circuit. This created a sudden surge and pop went one of the Red Luxeons, not much of a problem normally just replace it, except the LEDs were carefully installed on heat sinks behind tongue and groove wood panelling, the whole episode cost me a days work. Finally, I decided to use a voltage boosting circuit only and run it through an LM317 circuit I built a while back to limit the current, again a big word of WARNING here, avoid the simple ONE resistor only LM317 current limiting circuits, build one with a potential divider as I did. Because I bench tested on breadboard a simple LM317 circuit with a single power resistor and the damn thing allowed an initial surge of around 2 AMPs before settling down to the required current flow. In summing up the whole experience was dreadful and I hope I can save someone similar problems, always hook up the LED side first before powering up, check and check again on a bench test first before you even get to that stage, one more thing I did after this incident is I installed a 100uf 25-volt Tantalum Capacitor across the plus and minus rails to the LEDs, on powering up this effectively causes a momentary short circuit across the LEDs, forming a shock absorber to buffer any current surges. Bear in mind a capacitor across the LED supply rails could make things worse if you were to power up and then connect the LEDs up downstream of the Capacitor. I hope I have helped people avoid the problems I have just had to solve.

[@Electronzap]

Great video! I like that screwdriver cover for those annoying screw slots. I think I'll start using small alligator clip covers like that.

[@JulianIlett]

You can see the mismatch at low current, but wind up the power and it all looks good.

[@Llop66]

I would think the same ! I've been advised not to put LEDs in parallel with the same resistor. I would think the same about The DC/DC current limited PSU used in the video ! Especially when you know how behave a diode. But I'm a humble beginner !

[@johnsippitt14]

Hi Julian, Firstly, may I compliment you on your videos. Of all the electronics videos I have watched to date on KZbin yours are by far the best. Not only are you extremely clear and concise in you explanation of everything, but equally you ensure that what is important is shown on camera. I am slowly working my way through all you videos as they are a wonderful resource for so many, at all abilities. I am now unfortunately disabled and have been looking for a hobby I can manage from my wheelchair, electronics appears to be the ideal thing but I am very much a beginner. I’m sorry to be cheeky but I wondered if I could ask you for some advice please...my little grandson has a 12v battery powered “sit on” car and although I will not be able to fit everything myself I want to build a LED lighting project that my son in law can fit. I saw a video a while ago that shows the functionality that I would love to achieve and tried contacting the author. Unfortunately he is probably a very busy man and failed to respond. The video link is here: m.kzbin.info/www/bejne/pnWQeqGYob53os0 He mentions buck converters which I have investigated, but based on the type of small battery installed in these toys my research thus far seems to indicate think maybe buck/boost (or is it boost/buck) would be more suitable. With my very limited knowledge I have looked everywhere I can think of but cannot find one suitable so was therefore wondering if you could please possibly advise me accordingly as clearly you know this stuff inside out? The criteria that I am aware of appears to show the following considerations... 1. 12v battery Vin (I would guess this would vary as the battery is run down by use) 2. be as efficient as possible to minimise drain on the battery 3. have the ability to set both output voltage and amperage 4. be Arduino controlled so needs some form of “enable” or “switch” control 5. due to possible issues with heat I am guessing that 1w LEDs will be the brightest type I can use, and as his car only has 2 lenses on the front I’m envisaging that the largest circuit will consist of just 2 of these 1W LEDS. I’m guessing you’re a busy man too and although it’s going to take me a long time to figure all this out, simply by knowing which buck/boost converter to use will help more than you know., and based on some of the comments on the video previously mentioned, plus all the other online videos showing similar projects I think you could make a fortune if you designed and sold a schematic and/or circuit diagram for such a project. Sorry to bore you with all this but I’ll keep my fingers crossed you kindly reply. Thanks. Kind regards, John PS. Could you also please possibly list the 3 boards shown in this particular video? Thank you again

[@DeeJay1953]

I find I am always watching your videos when I am trying to learn. Thanks this is the best high powered LED video out there!

[@JulianIlett]

I think the 3rd pot is something to do with charging batteries. It alters the point when the fully charged LED comes on. Not completely sure about that though. The unit with the larger coil (with the visible windings) has a higher output current rating.

[@RustyNex]

thank you very much for that, it is interesting that they have still had to use multiple drivers, but never the less it looks like a great place to start

[@JulianIlett]

Thanks - the converter in the video uses the LM2596

[@1stUniqueName]

can you put LEDs in parallel like that????? I don't think so.

[@proyectosledar]

Excelent, julian. I do not like to connect leds in parallel, but if they are all the same thats ok.

[@JulianIlett]

You can buy dedicated 1W (or 3W) LED driver modules with an E (enable) connection for PWM control, but I can't think of a way to drive 10 separate LEDs from one driver module if you want individual control over each LED. You'd probably need 10 driver modules.

[@JulianIlett]

Try searching eBay for "RGBY Quadcolor 4*1Watt LED Built-in Driver Board LED" by Sure Display. It has 4 drivers on one board with PWM control inputs. The LEDs are pre-fitted but could be removed. Sure Display may have other driver boards that would be suitable.

[@DT-ge8gd]

P =V x I, so if it's 1 W, then 1/8.7 gives a current of 114mA. Not 300mA. Then P = I squared R, 1W = 0.114 x 0.114 x R, R =75 ohms. Use this resistor and you have no problems. You cooked the last one because you used a wrong resisitor. 33ohms is ~half the size required. Im not sure where you got the 300mA current from? I've used this method for years on all my led installs and never had a problem cooking any resistor, and the leds run cold as ice. I also don't use the Vf. I use the full voltage in case of a failure. So I would use 12V as the Voltage, not 8.7. Ive got my whole shed setup running 24 V leds on 2 12 V car batteries of 25Ah each in series and my house with 12 V batteries in parallel with 12V 6.5 W leds. I measured the current through the circuit first in the shed for each array and saw it was 600mA, and using the power calculation worked out its 14.4 W. Working it out is gives a value of 40ohms. So then the resistor I use is 15W and couldn't find a 40 so I use 44ohms. And resistor are cheap, so a little bigger is not an issue. I think they were $1.80AUS each. Ive had no issues with house or shed so hope I'm not doing anything wrong !! 😬

[@walterweigel4878]

Julian, thank you for your thorough and complete videos. Have you tried, or do you know if it is possible to regulate the intensity of the led’s in this array with an Arduino and mosfet using PWM in between the buck converter and the led’s? Thank you for your time.

[@RustyNex]

thanks for the reply, I know there are LED drivers out there that can control an array of LEDs, but i haven't seen anything for 1W LEDs, but thanks for the answer, i was thinking i would probably have to use individual drivers,

[@amitshalev4756]

Hi Julian! thank you for your videos , why do we need to regulate the driver voltage output if the current is already regulated ? thank you

[@sammy-pp1gl]

Julian ,best clear explanation , now I understand how it works . thanks pal

[@hawkercnc8261]

The accurate power supply control to the led is interesting and the problems caused by the alternator kicking in on a car to charge the battery. In car specific led exchange bulbs do they have any sort of regulation or resistance on board and are they doomed to failure more rapidly than the incandescent filament?

[@boffinschist1098]

I think I have worked out that the whole point of the driver is to limit the current enough so that the LEDs won't flicker when the voltage supply changes? I'm not sure if you said it like that or not. My LED string was drawing 155 mA without the driver and I turned down the current to 139 mA to make the flicker acceptable as my servo (wired in parrallel) was rocking back and forth).

[@boffinschist1098]

now I just need to boost the voltage instead of buck the voltage (whilst limiting the current). Any ideas for a board? Thanks

[@mikedalakis5292]

Informative and well presented. Thanks Much. ...... One day they'll make LED's that self limit the current??

[@dbbew]

3 watt show more simple for a MOTION SENSOR AND TRANSISTOR AS SWITCH AND 3.7 LITHIUM(4.2VOLT)AND HEATSINK AND DIODES FOR POWER REDUCTION MAYBE?THANKS

[@JulianIlett]

Yes, if the LEDs are in series.

[@MACYNET323]

Which module I can Use for drive 12V Led Strip on 12V Battery?The Linear Lm317 have too much Drop Voltage.Thanks for your Videos

[@haz939]

Would it make more sense to run a single 50w led or 3 x 13 3W leds? The 3W leds only need mounting on those 20mm star heatsinks. were as a 50w single led needs a massive heat sink. Would 13 x 3W leds give the same heat output all together as the 50w led? The main problem I have is the heat.

[@RustyNex]

i just had a look and they have some really great stuff, i think i will save that seller for later! but as for the drivers, i need them small because i am going to have a 24 grid of LEDs and the drivers can't take up too much room so i was thinking of designing my own based on the PT4115 driver, its very small and looks like it can handle up to 3 watts

[@BernhardHofmann]

The one I have from banggood has three blue boxes with adjustment screws. Would be nice if they had labels or a link to documentation online.

[@JulianIlett]

Try a search for "buck converter CC CV". There's one for sale by Bisany and another by Polelu.

[@jpbelcourt2796]

Just a warning about hooking leds in parallel. If one led fail, the other led in parallel with it wont last very long. Parallel circuits are current divider. If you cut one of the current path the totality of the current will flow trough the remaining path(s).

[@twotone3070]

In general if you remove one of the current paths the overall resistance will double hence halving the total current drawn. The voltage across the remaining load hasn't changed so the current through it remains the same. Having said that, whether by using these regulators, of which I have no experience, these rules change, I don't know. :)

[@RustyNex]

what would you do if you had an array of these LEDs? for example if you had 10 white LEDs and you wanted to PWM each one individually so they could all be at their own brightnesses, would you need a regulator per LED? surely if they were all using the same regulator then the load would change depending on how many were on or off.

[@teenflon]

Great video, just what I was after. One thing Im not sure of though is I want to have three LEDs that can be independently switched. Can I put three 1W LEDs in parallel and use a relay to turn some on and off or does it need to be all on or all off on the output?

[@jakelevi1996]

great video, very useful, thank you. Would it be possible to tell me the manufacturer and part-number of (a) the switch-mode voltage & current regulator and (b) the 1W LEDs that you used?

[@bassmasterflex77]

I'm trying to complete a project but need some additional info. I want to power a 3w rgb led for a project but I was told I may have an issue with the heat that they generate. I want to put it in a headlight housing so space is a factor would I be able to have a heat sink that will work properly in a tiny space and if I used the same board to power the led what could I use to control the color

[@NoFaithNoPain]

HI This is perfect for me thanks. However, if I want to put a Pot or rheostat type device on this to drop the voltage and therefore dim the LED's - where would I put it? Will the VR try to keep the voltage up if I put it in between VR and battery?

[@ErnestSigit]

Hi great video, Julian.Could you help me a bit? I'm making 100w panel ( LED 3w [2.2 - 2.6]v 700mA ) and i dont understand one thing. I will use computer power supply it gives 12v and arround 10 A. I'm thinking to connect buck power regulator for 5 LED in series and 14 row's. And the question would be, if one of the row's wouldn't work, so rest 13 row's would share that 700 mA? leading to massive LED's burn out? If yes, how i can protect my panel from this accident. Thanks for anwser.

[@dbbew]

SORRY FOR RAMBLING SIMPLY THESE CHEAP MOTION SENSORS AND 3 WATT LEDS ARE PERFECT FOR AN EASY DIY PROJECT.3 WATT LED,HEATSINK, MOTION SENSOR,TRANSISTOR,Photoresistor,3.7V LAPTOP BATTERY AND POSSIBLY CHEAP SOLAR CELLS AND THE LION RECHARGEABLE CIRCUITS TO KEEP CHARGED AWESOME MATE

[@farisk9119]

Hi, I have current source 900ma box. Input ac 220, output 12v labeled - Led and + Led. My Led 3 w, star Led same as on your video. My question can connect this Led direct as the box labeled which in this case I’m putting 12v on the Led or I should connect a series resistor which can drop the voltage across the Led? Thanks

[@ondrejstasek4454]

Hi, i need replace autobulb 21W/12V from reverse light. I can use 6x 3W smd led with only resistor? How to doo? Please help me

[@PilotPlater]

I'm wondering what would be a good solution for a traffic director like this: 36" Amber Traffic Directional Advisor Strobe Emergency Warning Arrow Stick I don't have a problem using smd parts, but wondering if there's any single-chip drivers, or a driver that would have some circuitry like one of these boards but multiple leads off it that I could switch with a micro and not blow anything up.

[@jimmymouez7365]

Hello Julian i've purchased the same voltage and current regulator to drive 3w leds , i' ve set the voltage to 3.3 v and the current to 700 mA as instructed on the data sheet however the led only drew 200 mA am i doing something wrong or it's just the quality of the leds . it's mounted on an aluminum heat sink and i got an additional heat sink but it did not heat up can you kindly advise ?

[@opidepartamentodeadministr1233]

how can i find a circuit like this,? voltage and current control

[@TiaCrafts]

I want to use the 3W RGB high power LEDs to light some fiber optic fabric in a costume. I've I'm only using 3.7V Lipo battery how hot will they get. If I put them on HeatSink will it be safe around fabric? Everything I read says those little high power lights get really really hot. Thank you!

[@JulianIlett]

Teresa Roberts A couple of problems here - 3W LEDs can get pretty hot, and you'll need constant current drivers between the LiPo and the LEDs. Probably better to use RGB LEDs with integral drivers like the WS2812B or APA102. I have videos on both of these.

[@vaivepatrick1550]

Julian ilkkelktkt

[@giuseppequartararo144]

Minute 3:43 what is name of this board? Tanks

[@NicholasAarons]

Fantastic Video Julian. Keep up the great work. Nick.

[@ktownc936]

Hi, my microscope led is the 3 watt star model. I burnt out the original circuit board because I plugged a 12 V wall charger instead of the recommend 5 V. So my question is can I use this led with a buck converter to allow a normal generic 12v to power it? Also need a dimmer switch attached to control brightness. Does anyone know how to go about this ?

[@broandrew]

Thanks for the video, I am making a UV resin curing lamp. How come you did not try 4 LED 3 watt lamps in series from the 12v battery? Did you give it a try? The bulbs I got were 3.2 to 3.4 volts

[@CluelessEngineer]

What's the exact name of the regulator. (Ex:lm2317)

[@ivowesterweele8757]

If you put a string in parallel and any one of the leds has a slightly lower voltage drop, you risk burning out the whole string. Better use one resistor per string, if more than one, even with a regulator

[@PilatusPorterPC6]

Ok......I bought some drivers on Ebay and they work good for 3w led's, which it says they are rated for. I think that the specs they give are wrong? Here is copy and paste from listing Also, these are NOT adjustable. ......Input Voltage: DC/AC 12 Rated voltage: 6-12VDC Frequency: 47HZ-63HZ Output Current: 300mA±5% Efficiency: ≥92% PCBA(L*W*H): 18*12*13mm Drive power: 1*3W....... I'm seeing more like 800ma current draw. So, these specs are wrong, correct? Next question...I ordered some other ones that say good for 1 to 5 1w led's. Do these possibly have some built in feedback to adjust voltage? I have not received them yet but they look the same. These drivers are driving me nuts!!!!!! : )

[@marwahmtp6995]

Hi there, can you please tell me what will happen if one string of led connected to CC driver fails to operate, as per my research it'll divide the total current into remaining string which as a result would damage them causing the whole system down. plzzzzzzzzzzzzzzzzz help

[@Sayeed3131]

I have bought 5w 700 mA LEDs that need to 6-7v to work . I want to install these LEDs as DRL in my car . I want to install 4 LEDs on each side using a cc cv module. Can u please help set the voltage and Ampere on the cc cv module to run 4 LEDs with car battery. Ill be thankful to you if u let me know the proper output voltage and current on the module to make the LEDs work without burning them

[@bondasfaq]

Please clarify this. The battery you are using is 7ah, the buck converter you have used can only take up 3amp (max 3amp input), you have connected it directly without any resistor. Why didn't the buck converter burned up? What if I connect my 105ah battery directly with the buck converter I have which input max current rating is 3amp, will my buck converter blow away? Please some one answer ASAP. Thanks

[@iwantitpaintedblack]

well not exactly an ASAP answer (4 months old) but anyways, buck converter can take 3Amps max, but it doesnt mean that it would take in as many amps as you give it, it mostly means that you can suck max 3 amps out of it, you can plug it into a 1000Ah battery it wont blow up if there is nothing connected to it, if you connect a 1A load it will suck 1A, and if you connect a 4A load (trying to power a 44'' plasma TV through the buck converter for eg) it would try to suck 4A and get warm, and probably blow out. LEDs are wierd because they have the ability to suck as much Amps as they get, thats why they would blow up so easily,

[@ananthanarayana5768]

From 230v ac I need to connect 20 1 w led so I think one rc circuit with buck converter I can use ? 66 volt 300ma I require

[@MichaelCrossUK]

Hello, thanks for the video it's very helpful - but I'm still a little confused about how to regulate my high power LED. I have a CREE XM-L2 U2 LED, which wants 3000ma at 3.5v for maximum power. I have a voltage and current regulator like the one in your video, it can deliver 5A. Do I need to regulate both the current and the voltage into the LED, or just the current?

[@isbestlizard]

can't you just stick a coil in series? any sudden change in current like a massive spike would cause a voltage drop across it and save the leds? :D

[@petrovski1948]

Julian, where did you acquire the converter, in the video, as I can only find one on eBay but the seller won't ship to the Uk? I assume you got it from China or Uk seller. Thanks

[@electro3976]

Hi Julian could you please do a video showing how to run 3W RGB with a pot to control brightness on each channel as there doesnt seem to be anything else out there on this topic

[@ilanbinkovitch6054]

Hi Julian. I got chinese 3W beads from aliexpress. using small buck-conv. with one trimmer on it: I set it to 3.4V, than measure Current to be 50mA (0.05A) , R = 3.4/0.05=68ohm. To list : 2.4V/0A=99k dark led; 3V/0.025=120 ; 3.2V untested ; 3.4V/0.05=68 (if 48.5mA R=70. 3% delta); 3.6/0.6=60 ; 3.8/0.075=50 ; 3.9/0.087=45 (if 97mA R=40. 11.5% delta ). Questions: 1. unsmooth form of R line 2. NOWHERE NEAR 300mA in your Ohm Law calc. could you enlighten US ? thanks

[@DeanHone]

Thanks for this post Julian .... where do you get your buck converters from. Mostly Ebay? Some no doubt are better quality than others.

[@evanleebodies]

Julian, In the 3s2p arrangement driven at 600ma, should any single LED develop a fault then surely the whole circuit will go faulty as the 600ma will momentarily flow through the branch without the initial faulty LED and overdrive that branch?

[@RespawnRestricted]

What's the thing you're using to adjust the pot I always find it a pain to use a screwdriver on them

[@TINBED291]

Dear Julian Great videos you have. what>model Buck>converter is this. The>Current buck converter ? Gr

[@umeshkodippili6481]

What is the common name for voltage-current regulator? Please newbie here...

[@prashanthb6521]

The one you saw in this video is a DC-DC converter.

[@mickd6942]

Hi, could i add a mosfet to the wires going to the 1 watt led as i need to feed the owtput from a pwm Board to make the led 1.5 kz with a duty cycle of on 7 off 1 , this is for a 1970's british army infrared Intrusion alarm set called IRIS i was given which only had 1 ir transmitter , i have made the system work with the pwm board and a 10 mm 850 nm led With resistor but will use 1 watt 940 nm led's To make 4 ir transmitters which need more current than the pwm board's can take.

[@johnberry5339]

Hi Julian another great tutorial, I am about to purchase one of these or similar modules but have noticed sometimes they are a blue board, or a red board. are they same? just different coloured boards? Thanks.... John :)

[@warezmonster4096]

Hi , if i wanted to use a 12v psu with a current and voltage regulator as in your example but for 3w leds that have a forward voltage of 3.4 and a 700ma current draw. could i run 6 - 2 rows of 3 from one 12v supply? assuming i set the voltage to 12v and the current to 1.4a?

[@ashwinzondag5828]

is there also an pwm input on this board. incase that I would like to dim the light by microcontroller?

[@Prabhu2086]

At 06:47 where the matrix led are powered that way, will both string of 3 series leds get 300mA each equally ? Or will one series led draw a different amount of current ?

[@boblenig3150]

could you tell me the source of the 12 volt regulator to buy? thanks not sure if it was in the description thanks again great videos, most ppl do not have any electricity knowledge

[@danielb7390]

Hi, I bought some 1W LED with the star back PCB. Can i run them at their nominal rating without more heatsink and not set them on fire? They shouldn't run more than 5minutes at a time.

[@Stewman029]

You said that it's impractical to use resistors with high powered LED's - Is that still true if you're running them from a more consistent power supply, such as a 12V power supply, plugged in to a wall outlet?

[@mellowb1rd]

a 12v wall adapter could be anything between 10 and 14V and have maybe 2 volts of ripple on it. That's less consistent than a battery

[@MagicCinema101]

Where could I buy the voltage regulator you use to regulate the battery.

[@nansovic]

HI, Great video. I have a question, what if you 9 leds in series/ 3 x 3 @ 900mA and one led in one series went out causing that entire 3 led in series to stop work, wont that overpower the other 6 @900mA. Thanks

[@kaelthassunstrider4559]

But how can i dim it with a MCU? I don't think a mosfet on the output or input would work or be a good idea.

[@deosinggih]

due the voltage change on battery so we need driver regulator for the led. What if I change power source with DC adaptor (I assume has steady voltage and current), do we need the regulator anymore? Or it can be done with only use resistor?

[@leedavis2812]

Hello, Thank you for the video! Does the output current remain constant throughout the battery's voltage drop (without adjusting)? Thanks!

[@nathanhatchel9836]

So if I wanted to drive 16: 1 watt leds with an arduino, I would need 4 constant current drivers and a transistor to switch each one on from the arduino pins?

[@viktorbozicevic6219]

Hi, I made myself for a spare time hobby a small 3D printed desk lamp, where I'm using a simple joule thief circuit to drive 3 of the 5mm white LEDs in parallel from a single AA battery. I bought a 3W white LED in order to make it brighter. When I connected it instead of 5mm LEDs, it lit a bit dimmer due to voltage drop. Checked with a multimeter: JT provides total of 22V through a diode without load and when I turn on the LED it drops to 2.3V at around 24mA current, I know that max. voltage for this LED is around 4V at higher current. Any ideas what shoud I modify to provide it with sufficient current? Do you maybe have good and simple references for this? Thanks!

[@dariocar7986]

Hy ! I have a question how to put a 1 W LED in my Makita lamp who have a ni-cd battery 9,6 v 1500 mA.Now i have on the lamp a regular bulb lamp but i wont to change with a led lamp. I think that 1 W is inaf for light on these lamp or I must put 3 W ? What led must I buy and can he work with only adding a resistor for adjust current ?? Sorry for the bad english because I am for Croatia. Can you give me an answer ?? Thanks Dario

[@Adam_C_anadian]

Hi Julian Great videos but the way! I have a few of this exact regulator, could I use it safely as a sub c batterie charger. I need to charge them individually so I have set the voltage to 2.3 volts and the current at 450 mA as they are 5000mA cells. Is that OK? And when they reach capacitie will the converter stop charging? The light is red while charging, will it turn green when they are full? Thx again! Adam

[@johnl6785]

Hi Julian, I am new to this LED. I am trying to learn. I have some of the small 3W LED which you have shown in your video. I like to use them for a lamp to convert to 12V so I can plug into 110V wall outlet. What kind of voltage current regulator would I need to use to support the LED. I like to use anywhere from 1 to 3 LED for the lamp. Thank you John

[@JulianIlett]

I did a quick search on eBay for "1W red LED" and found some with 655 - 660nm wavelength.

[@chrizero2319]

how would i run 120 - 3watt LEDS on one power supply connected to the wall ?

[@azzjo]

Hi I'm trying to retro fit some star 3w 700ma led's to my car as daytime running lights. Can you please give me some advice on the best way serial vs parallel etc. I need to fit 12 X 3w 3 - 3.6V 700ma but it will be 24 in total (12 LEFT & 12 RIGHT LIGHT). Please help

[@mellowb1rd]

I see many from this manufacturer with a third pot between the other two...what is that for? Duty cycle or something? Is it so you can use the driver as a dimmer or something?

[@j3tybaba]

+mellowb1rd The three pot version has charge ready LED on the pcb. It turns on when the current falls below a certain threshold value. With the third pot you can adjust the threshold current. This feature is only useful, when use the regulator for charging li-ion battery.

[@KelDG3]

Hi, a long shot asking on a video so old, but I have one of these constant current / voltage boards, I set it up for my IR 10W 5-6V 850-1000mA LED as Max 950mA and Max 5.5V, it seems to be getting fed the 950mA but when I do a voltage check on it, it only show 4.5V, any reason this might be?

[@ggesdsdsdsd]

Oh okay, is this buck converter only meant for battery's or could you connect it to a 12v power supply?

[@jonasgilje1645]

Is it possible to drive a 1W led with a 9V battery using the led driver shown at 4:25? Thank you.