My heart breaks (no pun intended) you have to include the CHF instruction for people that make negative comments. sad! Thanks for the instruction and circuit diagram. Good knowledge.
Hey paul, just saw your show on lighting led light,on this fine Saturday morning in upstate n.y. I. wanted to let you know,I've started my electronics hobby thanks to you and banggood.I'm very happy with arduino basic starting kit,the 37 in 1 sensor kit,and assorted other supplies from banggood.keep it going paul,I've learned a lot from watching you.
Thank you for that awsome video, it really has closed a gap in my knowledge that I've been fumbling with for a while. I'm off to my parts bin to see if i have all the bits to pull this one together. I really do feel like grasshopper being taught by the master in that old 80s tv series when I watch your vids. As always thank you for sharing your knowledge.
@@learnelectronics Thank you so much for your help, you are one awsome person. Since your video I've built the circuit and worked through the calculations and thanks to you have a much better understanding of the associated principles behind the build..
Also sir I am struggling we're trying to find knowledge on how to build a simple circuit to monitor and recharge lipofe4, if you could do some videos. I really I really think the simplicity of how you talk would help me to understand. I know with mosfets there is a way to provide the correct voltage and amperage after testing. It's revolutionary and I wish someone would just do it
I have a 30W UV LED that needs 32v at 1 amp so all the 30v lab supplies are just barely under the threshold. It turns on but to get full brightness I gotta bring up the voltage a tiny bit. Kinda like what you saw with his setup in the end when he had it at 9v and it stayed at 3mA. Such a pain having to build an extra circuit instead of just using the power supply on it´s own.
Great video. Should have given the equations and results for us newbies. i.e. running 9 LED's should draw around ( 9@15mA each= 135 mA) current draw. etc
Why am I bothered, but not surprised you need to include something about your physical condition because there are people who have brain worms and feel the need to make some terrible comments? You've got a lot of knowledge to give, and Ive spent the last couple weeks watching your videos and learning. The ability to learn something new by clicking on some videos links on YT is lost on people, sadly. I hope you don't spend too much time in your own head over some comments made by the human dumpster fires that seem to clog up YT comments. I'm learning from you. Thanks for that. fuck em.
Here's the project. I am adding a 274 nm LED bead to my hard shell N95 mask to help reduce possible infection. Will the coin battery with switch I am using power the LED bead? Not going to into particulars.
Hi, I have a current source driver 900ma, and one Led 3w. On current driver box, input ac 220v and output 12v and there is two points labeled as -Led and +led. I know Led has vf average 3.4v. There is something confused me, if I connect the Led as labeled that means I’m putting 12v on Led please correct me if I’m wrong! So I’m thinking to connect a series resistor to drop the voltage across the Led to 3.4v. What do you think please. Thanks
Very interesting. However, you didn't vary the input voltage coming from the power supply, which is more or less what I thought a constant current supply was all about. The current should remain relatively constant over the range of the maximum voltage that the regulator can tolerate. Varying the current limit knob of the power supply would prove the current limit function of the power supply worked, once you limited the output to less than the current limit of your attached circuit, but it doesn't seem that it demonstrates the constant current capability of the circuit you built. That said, it's a good circuit for driving LEDs, and is relatively inexpensive to build. The drivers that come with LED strip lights are problematic at low loads, such as when you trim a small number of LEDs from the strip to light a small area. This circuit is really good to drive them in a situation like that.
I agree, in this scenario I think a fixed resistor would have worked. If he would have varied the supply voltage it may have demonstrated the need for the LM-317's current limiting ability in this circuit.
The explanation is not complete for people with little understanding of electronics. As a matter of fact, this explanation will be a fail in an electronics exam. The LED requires a specific voltage according to its characteristics V/I. For this circuit to do it's job, the supply must provide at least the sum of voltages: Vled, I*R=1.25V, Vdrop LM317. The LM317 has a minimum drop of about 0.2V and a specific 1.25V between output and adjust pin. At 9.5V the circuit is not limiting the current, it's just providing the maximum voltage to the output, the resistor providing most of the limitation. Given the measured current of 120mA, the voltage across the LED is Vled=9.5-1.2-0.2=8.1V, which yields about 8.1/3=2.7V per individual diode, which is ~ the starting voltage for a high power led.
can this driver keep a constant current on a variable dc voltage, eg automobiles 12 volt system which may vary from 11 to15 volts or can it only work for 9 volts
I used to be a Patriots fan until Tom Brady left that's interesting with the lm317 I've used that to make a driver for a laser circuit for a diode laser it's also the same chip that's used
Put meter in diode mode. Red lead to led anode, black lead to cathode. If it doesn't light or you don't see a forward voltage on the meter, then the led is bad. Keep in mind not all LEDs will light from a meter. So let the forward voltage display be your guide.
Bits ordered to play, again! Although I will need heatsinks at some point! You actually did something similar using x2 LM317s with the 10W LED a while ago? I did not get to play with that one, so am going to give both circuits a go! Love the apps for the calcs too, thanks Prof... 👍🏻 💚 🐍
Well that seemed a lot more simple than I thought it would be. Whould it be possible to add PWM to this circuit to dim the light? and if so, where would it go in the circuit?
Thank you for the video. I watch almost all of your videos. Could you perhaps help me find a SPDT relay from china with coil voltage of 220'ish and with flat plug. I find nothing on aliexpress. Where do you buy relays?
Can someone please explain a little clearer how to calculate the needed resistor value for a given current? I get ohms law but I'm not sure how to apply it to this circuit for figuring out what value you need. And also, will this maintain the CC with varying input voltages? For example, running an LED off a battery, would the CC drop as battery voltage discharges?
You have to start by looking at the data for the LED. It will tell you what the current recommended is. Usually about 20mA. Now you know one part of Ohms law, I, the current. Then you should also know what your supply voltage is, say 9VDC. Now you have 2 sides of the triangle a can solve for the unk
@@learnelectronics but i mean, is the idea to size the resistor between output and adjust so that it's passing the desired current to adjust pin? That's the part I'm not sure of.
Yes. The manufacturer tells you the current for the LED. You know the supply voltage. So voltage divided by current equals resistance. That's how you figure out the correct resistor.
OK, that LED is nice. Very interesting project. So you generally need a heat sink with all LEDs? I've seen them in online stores, and know what a heatsink is, but didn't realize these had to have one.
How would one approach this problem from the other end of the scale? I have a reel of strip of 12v LED that you can cut to length and crimp connectors on to. What if one only wanted to use a couple of the LEDs in a model or very small project? I know nothing about the LEDs other than they require 12v.
They are usually in parallel and can be cut in multiples of four. Usually. So, 3V x 4 = 12V Still gonna need 12. Those strips take 12VDC no matter how you cut them,
Do you mean something like this: www.amazon.com/LEDwholesalers-Flexible-300xSMD3528-Adhesive-2026WW-31K/dp/B002QQ48TK If so then the dropper resistors are in place (as long as you cut on the cuttable sections) which means you can power it from any 12v supply without having to worry about current limiting...the LEDs take so little current I doubt you could find a plug adaptor/battery that had too little current to power them.
@@jonelectronics510 Yes, in fact that might be the very reel I have. I did find that the cheap wall wart they supply does not supply enough amperage for more than a couple feet of the tape used in another project, however. I had to use another supply to keep them from dimming beyond about two foot length of tape.
His videos really do make you want to get up and make something. The annoying thing is that whatever I feel like building, I am always One or Two components short, no matter what it is, lol.
Awww, why hate Patriots fans ! By the way, after switching to 10 Ohms, you could have shown the new calculation would be 1.25/10 which is around 125ma...pretty close to the 130 ma constant current it was showing there.
Because it's a breadboard demo! Running 10w into it in this setup it would overheat too quickly for the video. It's just a demo of the CC circuit not an implementation design guide.
You don't need heatsinks for that circuit ... I mean you do, but not if you want to truly entertain us! 😂 Make it smoke!! Make it smoke!! Just kidding ... let's be safe!
Do you know how I remember the equations? I know it’s not particularly politically correct but I was given this back in the seventies. Here goes. Women Are Virgins and Virgins Are Rare! Watts = Amps x Volts Volts = Amps x Resistance Something you never forget! Like 🐘🐘🐘
EExcellewnt. I have no problem with the math, but I can never remember which way round the equation goes. Funny how rhymes really help make things stick. Thank you.
Haze Anderson I would say that is grammatically incorrect 😁 Some English grammar is appalling on RUclips, even from apparently native speakers. Which often makes me cringe!
@@DeeegerD I grew up in a family of religious EEs and had never heard this before... until I met some hams at an antiques mall a couple weeks ago where they sell old tube gear. One of them asked me if I knew how to remember the color codes. I said no, they gave me this mnemonic device, and I almost died curled over in laughter! I will never have trouble remembering the order again =) Screw PC culture. Worth a good laugh and useful as well :D
My heart breaks (no pun intended) you have to include the CHF instruction for people that make negative comments. sad!
Thanks for the instruction and circuit diagram. Good knowledge.
Thank you my friend!
Perfect! This is just the type of LED I was looking to drive.
And I actually am watching on a Saturday so your greeting works out.
Hey paul, just saw your show on lighting led light,on this fine Saturday morning in upstate n.y. I. wanted to let you know,I've started my electronics hobby thanks to you and banggood.I'm very happy with arduino basic starting kit,the 37 in 1 sensor kit,and assorted other supplies from banggood.keep it going paul,I've learned a lot from watching you.
Thank you for that awsome video, it really has closed a gap in my knowledge that I've been fumbling with for a while.
I'm off to my parts bin to see if i have all the bits to pull this one together.
I really do feel like grasshopper being taught by the master in that old 80s tv series when I watch your vids.
As always thank you for sharing your knowledge.
You asked for it, you got it! Glad to help.
@@learnelectronics Thank you so much for your help, you are one awsome person. Since your video I've built the circuit and worked through the calculations and thanks to you have a much better understanding of the associated principles behind the build..
Ahhhh! So bright, screen has a hole in it now. 😄
Thank you Paul. Have a great weekend.
This is a really great video, I like the way you explain your understanding, so I can understand
Niners fan, from way back though
Also sir I am struggling we're trying to find knowledge on how to build a simple circuit to monitor and recharge lipofe4, if you could do some videos. I really I really think the simplicity of how you talk would help me to understand. I know with mosfets there is a way to provide the correct voltage and amperage after testing. It's revolutionary and I wish someone would just do it
Once again thank you
Damn. doesn't matter what topic, how old the topic how old the Video, but this guy always comes in clutch.
Thanks!
Found your channel by accident and became a fan. Keep up the great work.
You could use a 7809 with a diode inline with the ground to add 0.6 volts to the output.
Morning. watching before work. Keep up the great work, thanks again for the simplicity of your videos and instruction
great explanation, simple and easy to understand.
not vague or missing info like some...
Thanks for uploading :)
Great video Paul. I’ve got a few of these leds that run at 30 volts. They are a pain to light up, but you have given me an idea. You rock man.
I have a 30W UV LED that needs 32v at 1 amp so all the 30v lab supplies are just barely under the threshold. It turns on but to get full brightness I gotta bring up the voltage a tiny bit. Kinda like what you saw with his setup in the end when he had it at 9v and it stayed at 3mA. Such a pain having to build an extra circuit instead of just using the power supply on it´s own.
I watched it on Saturday, so happy Saturday to you. Thank you for the great videos.
Me too..years later!
Another great video, many thanks and I hope that you enjoy the rest of the weekend.
Have Fun,
Joe
Hi I am looking for a led driver for my 12v 50w led chip for a motorcycle headlight project any recommendations please.?
Great video. Should have given the equations and results for us newbies. i.e. running 9 LED's should draw around ( 9@15mA each= 135 mA) current draw. etc
well you just did
Why am I bothered, but not surprised you need to include something about your physical condition because there are people who have brain worms and feel the need to make some terrible comments?
You've got a lot of knowledge to give, and Ive spent the last couple weeks watching your videos and learning. The ability to learn something new by clicking on some videos links on YT is lost on people, sadly.
I hope you don't spend too much time in your own head over some comments made by the human dumpster fires that seem to clog up YT comments.
I'm learning from you. Thanks for that.
fuck em.
Here's the project. I am adding a 274 nm LED bead to my hard shell N95 mask to help reduce possible infection. Will the coin battery with switch I am using power the LED bead? Not going to into particulars.
Check out bigclivedotcom channel, he has done a fair bit about UV purification
funny coincidence i just happen to be watching this at 2am sat morning
People suck, ignore them. Thanks for the videos.
Hi, I have a current source driver 900ma, and one Led 3w. On current driver box, input ac 220v and output 12v and there is two points labeled as -Led and +led. I know Led has vf average 3.4v. There is something confused me, if I connect the Led as labeled that means I’m putting 12v on Led please correct me if I’m wrong! So I’m thinking to connect a series resistor to drop the voltage across the Led to 3.4v. What do you think please. Thanks
is it important to drive bigger LEDs at a high frequency?
Oh it's easy loi of Ohm I=P/U => 1A and R= U/I => 9.5/1 •~ 10 Ohm P=UI => 10W but very good demonstration thank you for sharing from Belgium.
LOL Watching this on 11/30/2024 "IT'S A SATURDAY" ....
Very interesting. However, you didn't vary the input voltage coming from the power supply, which is more or less what I thought a constant current supply was all about. The current should remain relatively constant over the range of the maximum voltage that the regulator can tolerate.
Varying the current limit knob of the power supply would prove the current limit function of the power supply worked, once you limited the output to less than the current limit of your attached circuit, but it doesn't seem that it demonstrates the constant current capability of the circuit you built.
That said, it's a good circuit for driving LEDs, and is relatively inexpensive to build. The drivers that come with LED strip lights are problematic at low loads, such as when you trim a small number of LEDs from the strip to light a small area. This circuit is really good to drive them in a situation like that.
I agree, in this scenario I think a fixed resistor would have worked. If he would have varied the supply voltage it may have demonstrated the need for the LM-317's current limiting ability in this circuit.
The explanation is not complete for people with little understanding of electronics. As a matter of fact, this explanation will be a fail in an electronics exam. The LED requires a specific voltage according to its characteristics V/I. For this circuit to do it's job, the supply must provide at least the sum of voltages: Vled, I*R=1.25V, Vdrop LM317. The LM317 has a minimum drop of about 0.2V and a specific 1.25V between output and adjust pin. At 9.5V the circuit is not limiting the current, it's just providing the maximum voltage to the output, the resistor providing most of the limitation. Given the measured current of 120mA, the voltage across the LED is Vled=9.5-1.2-0.2=8.1V, which yields about 8.1/3=2.7V per individual diode, which is ~ the starting voltage for a high power led.
Excellent. Thanks Paul.
How would you calculate the resistor value if you had a 20 watt 36 vdc led COB? Will the same transistor work for the example I mentioned?
Hi!
I bought a led driver which requires an input voltage of 5-32VDC. Can I simply use an adapter which has an output of 5V/2.5A? Please help. Thanks!
can i use L293D driver as the CC driver?
can this driver keep a constant current on a variable dc voltage, eg automobiles 12 volt system which may vary from 11 to15 volts or can it only work for 9 volts
I used to be a Patriots fan until Tom Brady left that's interesting with the lm317 I've used that to make a driver for a laser circuit for a diode laser it's also the same chip that's used
Cool vid thanks for sharing . Could you tell me how to test a LED driver and a LED light With a regular multimeter To see which component is bad?
Put meter in diode mode. Red lead to led anode, black lead to cathode. If it doesn't light or you don't see a forward voltage on the meter, then the led is bad.
Keep in mind not all LEDs will light from a meter. So let the forward voltage display be your guide.
@@learnelectronics ok thank you!
Once again, many thanks for this info.👍
Happy Saturday. Sorry about your condition.
Hi, can you comment on driving an LED steady like this video shows vs pulsed? Is it more efficient? can an LED be driven brighter ? thanks
2:15 can't you divide 10 by 9.5?
Bits ordered to play, again! Although I will need heatsinks at some point! You actually did something similar using x2 LM317s with the 10W LED a while ago? I did not get to play with that one, so am going to give both circuits a go!
Love the apps for the calcs too, thanks Prof... 👍🏻 💚 🐍
Yep, you remember that video, cool.
Well that seemed a lot more simple than I thought it would be. Whould it be possible to add PWM to this circuit to dim the light? and if so, where would it go in the circuit?
You can just vary the voltage to dim it. So you would put the PWM on the VCC
@@learnelectronics Magic, thank you.
Can lm317 be paralleled for higher current requirements? This video helped me alot but I may need higher currents in my next projects.
Nice video but it would have been even better if you had designed an adjustable current source for this application...
ats89117
An adjustable 10 ohm, 10W resistor is expensive and hard to obtain.
How do I drive a 75w 905nm 12v 30A laser diode ?
Thank you for the video. I watch almost all of your videos. Could you perhaps help me find a SPDT relay from china with coil voltage of 220'ish and with flat plug. I find nothing on aliexpress. Where do you buy relays?
Can you do one of these for RGB 10watt LED? I know the values will be different, looking to see how YOU would build it. Thanks!
I will have to get one
Can someone please explain a little clearer how to calculate the needed resistor value for a given current? I get ohms law but I'm not sure how to apply it to this circuit for figuring out what value you need. And also, will this maintain the CC with varying input voltages? For example, running an LED off a battery, would the CC drop as battery voltage discharges?
You have to start by looking at the data for the LED. It will tell you what the current recommended is. Usually about 20mA. Now you know one part of Ohms law, I, the current. Then you should also know what your supply voltage is, say 9VDC. Now you have 2 sides of the triangle a can solve for the unk
@@learnelectronics but i mean, is the idea to size the resistor between output and adjust so that it's passing the desired current to adjust pin? That's the part I'm not sure of.
Yes. The manufacturer tells you the current for the LED. You know the supply voltage. So voltage divided by current equals resistance. That's how you figure out the correct resistor.
Verry usefull ...content vedio..i find ..now this circuit
OK, that LED is nice. Very interesting project. So you generally need a heat sink with all LEDs? I've seen them in online stores, and know what a heatsink is, but didn't realize these had to have one.
Great man! Very, very great job! Thanks a lot!
How would one approach this problem from the other end of the scale? I have a reel of strip of 12v LED that you can cut to length and crimp connectors on to. What if one only wanted to use a couple of the LEDs in a model or very small project? I know nothing about the LEDs other than they require 12v.
They are usually in parallel and can be cut in multiples of four. Usually. So, 3V x 4 = 12V Still gonna need 12. Those strips take 12VDC no matter how you cut them,
Do you mean something like this: www.amazon.com/LEDwholesalers-Flexible-300xSMD3528-Adhesive-2026WW-31K/dp/B002QQ48TK
If so then the dropper resistors are in place (as long as you cut on the cuttable sections) which means you can power it from any 12v supply without having to worry about current limiting...the LEDs take so little current I doubt you could find a plug adaptor/battery that had too little current to power them.
@@learnelectronics Thank you for taking the time to reply. I very much appreciate it!
@@jonelectronics510 Yes, in fact that might be the very reel I have. I did find that the cheap wall wart they supply does not supply enough amperage for more than a couple feet of the tape used in another project, however. I had to use another supply to keep them from dimming beyond about two foot length of tape.
Don't you have to consider the dropout voltage of the regulator as well?
Not for this.
Really nice! 😃
Those ceramic resistors are killers, especially when you have limited space on a pcb!! Great video ;)
Where lost Electric?
REMEMBER - Multimeter Fuses are expensive!
No Patriots fan here. Good circuit, thanks, Paul!
Awsome one bud.
Thanks Paul 👍
Excellent, thanks.
Simple and effective!
It is actually a Saturday!
Thanks Paul.
Lol watching on Saturday 🤓😂
I want to dive into electronics now.
His videos really do make you want to get up and make something. The annoying thing is that whatever I feel like building, I am always One or Two components short, no matter what it is, lol.
Awww, why hate Patriots fans ! By the way, after switching to 10 Ohms, you could have shown the new calculation would be 1.25/10 which is around 125ma...pretty close to the 130 ma constant current it was showing there.
V=9.5, I=0.120A then Power=1.14W. you are driving 10W led with 1.14W of power.
Because it's a breadboard demo! Running 10w into it in this setup it would overheat too quickly for the video. It's just a demo of the CC circuit not an implementation design guide.
It is Saturday at the time I'm watching this😮
Thank you
Happy Anyday!!! Stop teaching me things!!! Lol!!
respect from Brunei Darussalam..❤
Ciee uwang brunei
By OP Amp, sir - please :)
Hi happy sat to you two nice video god bless you
Jokes on you friendo, it IS a Saturday 😂
Nice video
No Cheateriot fan here!
Thank you sir
Thanks!
Nice video :-)
You don't need heatsinks for that circuit ... I mean you do, but not if you want to truly entertain us! 😂 Make it smoke!! Make it smoke!! Just kidding ... let's be safe!
No smoke, no smoke...bad for lungs! lol
Crap I thought breathing this stuff was making my brain cells multiply ....
Anyone who needs much less owns a ohms law calculator is not an engineer. Reu the other way as fast as you can.
Do you know how I remember the equations?
I know it’s not particularly politically correct but I was given this back in the seventies. Here goes.
Women Are Virgins and Virgins Are Rare!
Watts = Amps x Volts
Volts = Amps x Resistance
Something you never forget! Like 🐘🐘🐘
EExcellewnt. I have no problem with the math, but I can never remember which way round the equation goes. Funny how rhymes really help make things stick. Thank you.
You can also replace Are with Is 😏
Haze Anderson I would say that is grammatically incorrect 😁
Some English grammar is appalling on RUclips, even from apparently native speakers. Which often makes me cringe!
@@DeeegerD I grew up in a family of religious EEs and had never heard this before... until I met some hams at an antiques mall a couple weeks ago where they sell old tube gear. One of them asked me if I knew how to remember the color codes. I said no, they gave me this mnemonic device, and I almost died curled over in laughter! I will never have trouble remembering the order again =) Screw PC culture. Worth a good laugh and useful as well :D
Magic! I just got some from ebay (10w) so your vid is useful.
saturday
If you are that is inough
I can't believe you need a calculator to solve R and I. How hard can be to solve it hand?
Ha ha ha!! Damned Pats fans!
Io