This series is a gem! I don’t know anything about electronics but my 10 yr old son is SUPER interested in it. Finding videos that explain the topic so clearly (and, honestly, entertainingly) that we both can stay engaged with, understand, and talk about these concepts was very challenging. So I’m very grateful that you took the considerable time and effort to create this series, and make the world a better place than you found it.
My first job after getting my BSEET degree from College was at the Trans-Lux Corporation, manufacturers of large scale LED displays. At the time, only yellow, green & red LEDs, mostly for the NYSE, AMEX, CBT & CME. I was the LED Specialist, responsible for equal radiation profile for all LEDs in a scrolling display. One day, we got a sample, a Blue LED ($500) that was barely 20 Candellas. But it was a whole new ballgame. Engineers flocked around it like babies to a Christmas Tree. From that humble beginning, we were able to feed RGB Video to the new RGB LED displays and revoluionized the Full Spectrum Large LED display market! I was There! yo.
Man your channel is wonderful. As a software developer trying to go deeper into learning about the internet of things your content is just what I needed to not stay lost.
Thank you, this is just what I need. I want to try putting lights into various projects but I also want to do it right and keep it safe. I had doubts about whether tiny LEDs with batteries could be a fire hazard (I'm starting from zero here so I need the core knowledge) and now that I see what can happen, I know I was right not to rush in. But the great bit is knowing why. I don't like stumbling in blindly. I watched another video here where a dude just snipped off both wires and soldered the thing to some copper wire and then a switch without worrying about resistors or which wire was which. He said you had a 50% chance so no worries.The comments below it were full of people basically tearing their hair out in exasperation so I thought I'd better find a quality source of information before I even buy the supplies... outside of the soldering materials, which I have.
Thank you!! I am learning so much about the basics in Electricity. I have been looking for basic teaching like this for weeks. I’m so glad I found your playlist full of knowledge. I love your videos, and they are so educational. Thank you for all you do!
I've always loved LEDs, ever since I got my first electronics project kit from Radio Shack as a kid. I was fascinated by the soft pure red light they put out. That was back in the early to mid 80s, long before blue or white LEDs hit the market, or anything with a high intensity output. Great video! I'm always looking forward to the next one. I used your laser tripwire project to make a circuit that will be used to open up a solenoid valve to release a jet of compressed air and scare birds away from making nests on my house. It's almost complete and needs a good box to put it into so I can mount it on the side of the house next spring.
I've been playing with semiconductors for a long time now and have always enjoyed making circuits just for fun, your site has sparked new interest, thanks...
Once I was at a casual robotics workshop (making things move) and the LEDs supplied by the organisers were cheap chinese ones with inverted leads: shorter Anode, longer Cathode. I've been using the death test to figure out max current for a while now, and my Fluke tells me the Vf when I test a diode. Good to see more frequent videos from you again, by the way :)
I thought of my daughter as I nearly blew us up that time. No one was Arnied fortunately but I still am alone in the lab 😂. Some things are meant to be.
So far this is the best and most concise I have found on the subject. I am a woodworker trying to incorporate some LED lighting into some of my power tools like all my routers, mitre saw and a few others so I am trying to understand how the basics work in order to incorporate an integrated LED driver directly into the tools' body to run some LEDs at directly at the cut. This has helped immensely along with some of your other videos and been an instant subscription. Thank you.
I want to start using LED's in my model building. I am VERY electrically ignorant. This very short video was incredibly informative. Thank you for educating me.
Concerning forward drop voltages, there are two different types of green LEDs in production, one that is phosphide-based (yellow-green), another that is nitride-based (blue green). It appears that older green LEDs tend to be the former type, and newer units are typically the latter type.
Thomas Edison did not invent the incandescent light bulb from scratch, but he did produce the first practicably usable one. He filed for a patent on the filament-based light bulb in November, 1878. He did not get the idea from Tesla, who emigrated to the United States in July 1884, having produced nor patented such a device. Tesla is best known for his work with alternating current, essentially inventing the modern AC power grid still in use to this day, much to the chagrin of his competitor Edison, who did everything he could to sabotage Tesla.
As the narrator said, Edison invented the first commercially viable incandescent bulb. Just as importantly, he invented and installed a practical and profitable electrical power generation and distribution system to support electric lighting.
Edison's system was NOT practical in any sense of the word. It was inefficient, ABSOLUTELY unsafe, impractical to distribute and hideously EXPENSIVE. Plus, you could be killed simply by walking over the buried cables during a rain storm. Dogs would scream and horses would bolt when crossing Edison's buried cables.
That's neither true nor an interesting conspiracy theory. Even the mercury-containing compact fluorescent light bulbs, which are totally different from LEDs and look nothing like them, are very safe relative to something like a mercury thermometer, which many people over 50 never worried about having in their homes.
I just repaired an LED magnifying lamp. Apparently, there were many LEDs that were burnt out or simply tired. The circuit is 16 x 6 LED strings in parallel to an 18 VDC supply. Half the strings were either flashing or simply not on. Instead of trying to discover which LEDs were bad, I simply replaced an entire string. The new LED's are much brighter than the old ones. I may just replace all of them.
I found your channel some time ago, but it hadn't been uploaded to in some time. I remember your website from my high school years. Are you the same creator that brought us such great hits as the super megason IV review, the home made wireless charging mouse, and penny ram heat sinks? If so you provided my friends and I hours of hilarious entertainment. It is great to finally get the opportunity to thank you for helping cultivate our passion for electronics. This channel you have made is amazing. Glad to see you are still doing well and that you have found a way to educate people while still keeping a touch of that flare for humor I used to love! It would be great to know if you still have some of those old articles from you website somewhere. I'm sure people would still find your musical hard drives, among other creations, funny and fascinating.
Nice! The electric current (flow of electrons) actually comes from the minus (-) and goes towards the plus (+) but most of the time that's not very important.
When I started to learn electronics, only red LEDs were available and green ones came out a while after. Then later I saw a three color LED at a Radio Shack store, which could glow yellow when connected to an alternate current source. It was glowing green when connected in reverse polarity. One day I shook it while it was yellow then noticed it was alternating between red and green. So cool I felt that day. Before I saw blue ones then finally the white ones, many many years passed.
No, that was really Aemer's question. I was just following up, because usually certain letters are reserved for certain things. Plus, you can't know that "nobody cares," because you're not a mind reader.
Good video and well presented too. I haven't dabbled with electronics since a young lad and things were a lot different then, valves were pretty important then for a start, so I've got a lot of catching up to do. I think your channel is just what I need, thank you.
i saw an ultra bright LED flashlight video on UA-cam... Can you (or are you going to? if yes, then when?) make some CRAZY things that we can do with electrical components (as a series)? Like, the ultra capacitors was pretty CRAZY, it would be fun to know how a simple component we use, can do on a super saiyan mode.
I hope you finally come back and i don't need to wait 3-6m for a video :( i really like your channel. This channel help me a lot with my electronics projects :D Thank you @Afrotechmods
3:47 : magic smoke ! It seems there is a clicking sound (relay?) coming from the powersupply at some point while it is switching between constant current and constant voltage modes. Seems it still limit current somehow (to protect itself?)
The voltage for led lights is dependent on what light they are built to emit. Take 1240/wavelength of light emitted to get the eV. eV are called electron volts for a reason since they are for every electron that gets excited in the LED, it emits a photon and best does so at that voltage due to the bandgap energy of the piece of semiconductor inside the LED. High voltage will overheat the light when so many electrons going through very quickly just like anything that short circuits and overheats.
this might be a dumb question, but how come in this video at 4:40, i see you have your resistor installed on the cathode to the black lead to your PSU? but in your NEXT video following this about resistors, you are adding the resistor to the red anode side of the circuit? does it not matter where you place your resistor?
I once bought a couple of larger UV LEDs to build a UV flashlight but the shop i bought them from did not have any data on them. Is it possible to find out the forward voltage with only a basic multimeter without destroying one of the LEDs? Or do i have to look around for something that looks similar and hope for the best? Thanks for the informative videos!
Yes, it's very easy. Put a 1k or so resistor in series with the LED and power it up. Then use your multimeter set to measure DC voltage, and measure the voltage across the LED. That's the forward voltage!
There are Three ways to tell the cathode from the anode: the two you mention and looking inside the clear plastic: the *Cup-shaped* side is the *Cathode* side. C = Cathode
If you don't know the forward voltage of your LED, use a power supply which has a constant current mode and can display voltage and current. Turn up the voltage until your LED draws 20mA. The voltage is your forward voltage. Use that to calculate a suitable resistor. Not all LEDs run well with 20mA. The high power ones generally run with 300-700mA. They get really hot, so don't forget the heatsink.
OMG!!! Best videos I’ve ever seen regarding this subject. So informative, comprehendable, and easy to understand, I even took notes!!! Thank you so much for these!! Subscribing!!
awesome video as always ! for me i usually know the cathode from the anode is by the metal area inside the plastic the cathode is bigger we usually say "the flag side is the cathode" sorry for my bad english
Confused on one thing, prior video you explained how electron flow is actually negative to positive but in this one you say the anode is suppose to connect to positive side and the flow of electrons go from anode to cathode, which is backwards from other video. Am I missing something?
I recall, back in the late 70s, red LEDs were available, though very expensive. They glowed, rather than shined. In 1980, I bought a pack of 50 once, for a light chaser project. They cost quite a bit. I never did complete that project and that pack is still around somewhere. Then came green LEDs and suddenly the technology was interesting. Blue were first announced in a Dutch magazine called Electra. TVs screens couldn't be that far behind.
Hi, Fist of all, i liked the way you presented the concepts. very clear, simple and to the point. Very nice. Secondly, I was trying to check the next video on Resistor, but am not able to find it on your channel. can u share the link plz?
You can also show how junction temperature change impacts performance when driving an LED with Voltage and ballasting with a resistor. Better to drive using a constant current source, but this is not cost effective commercially.
love this 101 LED tutorial . Question . I have a winding path thru the woods of around 1,000 ft long. I would like to string some LEDs above it for indicating the path at night ..like lights on the floor of an aircraft for emergency exit. There is no 120 AC volts at that location so I was wondering how to do it with solar . Now , I see solar being used on electric cattle fences emitting DC power. One wire carries current in a pulsating manner and is grounded at the other end . Can I use such a system , trough a DC batt. by connecting one wire to the anode and run a seperate wire to ground ?
Thanks for blowing up those LEDs without the current limiter ... saves me from having to demonstrate this myself to my students and burning out my own LEDs! 😆👍
Where did you find the table of voltages of the different LED's? I find it peculiar that the blue and white LED are not said to have the same Vf - After all a white LED is just a deep blue (royal blue) LED with phosphor on top, so the Vf should be (and is generally, apart from small differences in chemistry) the same.
The respective LED datashit has that information. For example here: www1.futureelectronics.com/doc/EVERLIGHT%C2%A0/334-15__T1C1-4WYA.pdf Go to the fourd page, there is a table that says: "forward voltage", and there the min. voltaje is 3.0v and the max. voltaje is 3.6v
Red, orange, yellow, and 570 nM green usually have a a fV of around 2 volts while 525 nM green, blue, and white around 3 volts. IR LEDs are around 1.6 volts. Read the data sheets and uses these numbers only as a guide if there is no data available. Current is another story, a data sheet is required. Most 3mm (T1) or 5mm (T1-3/4) have a rating of 20mA as do the smaller SMT packages. The data sheets are important especially once larger packages and wattage ratings of LEDs are used. A white LED is in fact a blue LED with phosphor on the lens. A manufacturer may have blue and white LEDs that use the same die and have the same voltage and current ratings. The same can occur with white LEDs of different temperatures. Warm white (2700 - 3500K) usually have a lesser light output as the phosphor is thicker and of a different composition than that of a neutral (4000-5000K) or cool white (5000-6500K) LED. The same die may be used to produce white LEDs of all of the different color temperatures. The color of the phosphor on a warm white LED has a visible reddish tint and tends to block more light than that of neutral or cool white LEDs and lessens the light output..
One should also be aware that some coloured (red, yellow, orange, green etc) LEDs are actually using the same technique as white LEDS - using a blue LED internally and using phosphors to generate the visible colored light. For these the usual rule of varying forward voltage by colour doesn't apply. For instance used in some simple Christmas/fairy light strings where all the LEDs are wired in parallel and all run at the same voltage without needing resistors to adjust for varying forward voltages And if you're buying LEDs from China (eBay, AliEDxpress et al) sometimes batches have the pins reversed (ie the long one isn't the anode). They can even have the semiconductor chip reversed inside, so not even which leg that is connected to the 'anvil' (the larger internal piece of metal) is a sure thing. Never assume - test.
If you are too stupid to know what "commercially viable" means then don't bother leaving a comment about Thomas Edison.
Woah recent update. Dude please come back!
Also, who is this comment for?
Smart ass.
Gee, now I want to know who said what, lol!
@@flyurway Same
@@flyurway Name names
Love this video! You take me back about 30 years blowing up LEDS. I love when things are explained simple, so everyone can understand. Thanks!
This series is a gem! I don’t know anything about electronics but my 10 yr old son is SUPER interested in it. Finding videos that explain the topic so clearly (and, honestly, entertainingly) that we both can stay engaged with, understand, and talk about these concepts was very challenging. So I’m very grateful that you took the considerable time and effort to create this series, and make the world a better place than you found it.
My first job after getting my BSEET degree from College was at the Trans-Lux Corporation, manufacturers of large scale LED displays. At the time, only yellow, green & red LEDs, mostly for the NYSE, AMEX, CBT & CME. I was the LED Specialist, responsible for equal radiation profile for all LEDs in a scrolling display.
One day, we got a sample, a Blue LED ($500) that was barely 20 Candellas. But it was a whole new ballgame. Engineers flocked around it like babies to a Christmas Tree. From that humble beginning, we were able to feed RGB Video to the new RGB LED displays and revoluionized the Full Spectrum Large LED display market! I was There! yo.
I liked this story thank you
Woow
Stephen Beres how seven segment display get made?
Stephen Beres
Best story this year! yo.
They have Mercury inside?!
I love the new round of super-basic videos. They will be great for my classes with the younger students. I am looking forward to the next one.
I'm a visual learner...so the demonstrations are really helpful and make it easier for me to retain the information. Can't wait to view more videos
Man your channel is wonderful. As a software developer trying to go deeper into learning about the internet of things your content is just what I needed to not stay lost.
"don't try this at home." I already did. That's why I am here.
:D
Been there, done that.
James Scobie hhg
Maybe you needed to come here first
😂😂😂
Thank you, this is just what I need. I want to try putting lights into various projects but I also want to do it right and keep it safe. I had doubts about whether tiny LEDs with batteries could be a fire hazard (I'm starting from zero here so I need the core knowledge) and now that I see what can happen, I know I was right not to rush in. But the great bit is knowing why. I don't like stumbling in blindly. I watched another video here where a dude just snipped off both wires and soldered the thing to some copper wire and then a switch without worrying about resistors or which wire was which. He said you had a 50% chance so no worries.The comments below it were full of people basically tearing their hair out in exasperation so I thought I'd better find a quality source of information before I even buy the supplies... outside of the soldering materials, which I have.
Thank you!! I am learning so much about the basics in Electricity. I have been looking for basic teaching like this for weeks. I’m so glad I found your playlist full of knowledge. I love your videos, and they are so educational. Thank you for all you do!
Brilliant, simple, easy, and clear instructions. Who could ask for anything better than this tutorial?
You explain it so well for the layman. Awesome! I only wish I could explain it so simply and be interesting at the same time.
No way, new videos from WhatYouOughtToKnow and Afrotechmods in the same day?? Is this heaven??
I'm really happy that you're back. You have a good way in explaining. I hope you're here to stay for a long time!
I've always loved LEDs, ever since I got my first electronics project kit from Radio Shack as a kid. I was fascinated by the soft pure red light they put out. That was back in the early to mid 80s, long before blue or white LEDs hit the market, or anything with a high intensity output.
Great video! I'm always looking forward to the next one. I used your laser tripwire project to make a circuit that will be used to open up a solenoid valve to release a jet of compressed air and scare birds away from making nests on my house. It's almost complete and needs a good box to put it into so I can mount it on the side of the house next spring.
Sounds cool
I've been playing with semiconductors for a long time now and have always enjoyed making circuits just for fun, your site has sparked new interest, thanks...
Once I was at a casual robotics workshop (making things move) and the LEDs supplied by the organisers were cheap chinese ones with inverted leads: shorter Anode, longer Cathode.
I've been using the death test to figure out max current for a while now, and my Fluke tells me the Vf when I test a diode.
Good to see more frequent videos from you again, by the way :)
FYI for German viewers: In German, simple to remember the leg length: "Kurz" (German for 'short') for "Kathode". So the short wire is the cathode.
Henner Zeller Guter Tip, werd ich mir merken!
Malte. ich mir auch
Henner Zeller and how do I remember what the cathode does. its always try and error for me:D
think of *c* o l d ( *c* a t h o d e ) as in *minus/negative* temperature :)
ABaumstumpf 7
I love the brain. When the LED fried at 3:50 i smelled the smell of burned LED's.
Good and short video, very precise.
I thought of my daughter as I nearly blew us up that time. No one was Arnied fortunately but I still am alone in the lab 😂. Some things are meant to be.
So far this is the best and most concise I have found on the subject. I am a woodworker trying to incorporate some LED lighting into some of my power tools like all my routers, mitre saw and a few others so I am trying to understand how the basics work in order to incorporate an integrated LED driver directly into the tools' body to run some LEDs at directly at the cut. This has helped immensely along with some of your other videos and been an instant subscription.
Thank you.
Clear and conscious, easy to understand even for a guy like me - job very well done,
Cheers.
I've literally searched the internet for an explanation like this! Amazing, and finally lol!
Sadly this channel died
@@fahoudey what? Why?
@@fahoudey yeah true, do you know if there's a specific reason?
I want to start using LED's in my model building. I am VERY electrically ignorant. This very short video was incredibly informative. Thank you for educating me.
Concerning forward drop voltages, there are two different types of green LEDs in production, one that is phosphide-based (yellow-green), another that is nitride-based (blue green). It appears that older green LEDs tend to be the former type, and newer units are typically the latter type.
Afrotechmods is finally back🙌 Thank you😀
Check my channel there may be some recent videos you missed.
You've been missed, sir!
Thomas Edison did not invent the incandescent light bulb from scratch, but he did produce the first practicably usable one. He filed for a patent on the filament-based light bulb in November, 1878. He did not get the idea from Tesla, who emigrated to the United States in July 1884, having produced nor patented such a device. Tesla is best known for his work with alternating current, essentially inventing the modern AC power grid still in use to this day, much to the chagrin of his competitor Edison, who did everything he could to sabotage Tesla.
As the narrator said, Edison invented the first commercially viable incandescent bulb. Just as importantly, he invented and installed a practical and profitable electrical power generation and distribution system to support electric lighting.
Edison's system was NOT practical in any sense of the word. It was inefficient, ABSOLUTELY unsafe, impractical to distribute and hideously EXPENSIVE. Plus, you could be killed simply by walking over the buried cables during a rain storm. Dogs would scream and horses would bolt when crossing Edison's buried cables.
Wow, hello again Afrotech. Still loving the old sites stuff. Thanks for staying online and making new stuff.
A million thanks to you, now I know why my LED stop lighting on when I connect it to 9V Battery.
And how much did you destroy?
Diodes are pretty darn cool!
Not if you put enough current through them. HA!
_So many thumbs down!!_
Must be *_PEOPLE for the ETHICAL TREATMENT of LEDs_*
The technology is great, however these LED bulbs have Mercury! When lit for periods at a time, it seeps into your homes!
That's neither true nor an interesting conspiracy theory. Even the mercury-containing compact fluorescent light bulbs, which are totally different from LEDs and look nothing like them, are very safe relative to something like a mercury thermometer, which many people over 50 never worried about having in their homes.
Richard Head,
The thumbs downs are probably because he told everyone the voltage to use, but not watt (pun intended) resister to use.
Or unethical treatment of their heads - made them hurt, too much information.
Ok
I am trying to make a plane model detailed with fully functional Gear, Lights, etc. This will be my first step.
I'd like to know how it turned out please. I would think that the flight functionality would be advisable to work on first
So? Is it finish
I abandoned this project due to things I forgot, but since we're in a pandemic, might as well try again.
I just repaired an LED magnifying lamp. Apparently, there were many LEDs that were burnt out or simply tired. The circuit is 16 x 6 LED strings in parallel to an 18 VDC supply. Half the strings were either flashing or simply not on. Instead of trying to discover which LEDs were bad, I simply replaced an entire string. The new LED's are much brighter than the old ones. I may just replace all of them.
You are finally back, i am so glad
I found your channel some time ago, but it hadn't been uploaded to in some time. I remember your website from my high school years. Are you the same creator that brought us such great hits as the super megason IV review, the home made wireless charging mouse, and penny ram heat sinks? If so you provided my friends and I hours of hilarious entertainment. It is great to finally get the opportunity to thank you for helping cultivate our passion for electronics. This channel you have made is amazing. Glad to see you are still doing well and that you have found a way to educate people while still keeping a touch of that flare for humor I used to love! It would be great to know if you still have some of those old articles from you website somewhere. I'm sure people would still find your musical hard drives, among other creations, funny and fascinating.
Me too.
This is a component that instantly attracted my attention as a kid, about three decades ago.
The cathode of a device is indicated by the letter "K" not "C". The letter "C" is used to indicate a collector. See IEEE 315 Clause 8.4
2:28 - The maximum allowable reverse voltage of many LEDs is actually quite low, perhaps only 5 or so. Reverse insertion can indeed damage them.
Nice! The electric current (flow of electrons) actually comes from the minus (-) and goes towards the plus (+) but most of the time that's not very important.
Conventional current (which is used in electrical engineering) flows from positive to negative.
Yup, electrons don't like hanging out together in big crowds for too long, too many negative vibes
welcome back mr afrotechmods
Like a professor you nailed it on our brains 👏👏👏👏👏
When I started to learn electronics, only red LEDs were available and green ones came out a while after. Then later I saw a three color LED at a Radio Shack store, which could glow yellow when connected to an alternate current source. It was glowing green when connected in reverse polarity. One day I shook it while it was yellow then noticed it was alternating between red and green. So cool I felt that day. Before I saw blue ones then finally the white ones, many many years passed.
You explained it very well. I also like that fact that you used the DC power supply. Thank you for sharing. Thumbs up for you. I just subed!
Glad it was helpful!
Okay, I am hooked, your instruction is extra-ordinary.
I would listen to any book you narrate . awesome voice .
If you cant remember which is Anode and Cathode, remember that + comes before - and A comes before C => (+A) (-C)
Great Video!
Wait... @1:35 Why is the cathode a "C' rather than a "K"? I thought this was meant to prevent confusion for C for Capacitor.
C and K are both used.
But why _ever_ a c, if "c" was supposed to have been reserved for "capacitor"/"capacitance"?
Whom are you trying to reply directly to, ABaumstumpf?
So how is that supposed to answer my question, Baum?
No, that was really Aemer's question. I was just following up, because usually certain letters are reserved for certain things.
Plus, you can't know that "nobody cares," because you're not a mind reader.
Crikey chap! You have a real talent for this!
Your tutorials are the best man I watched all of them, please post more, I already see that a lot of people like them too
Good video and well presented too. I haven't dabbled with electronics since a young lad and things were a lot different then, valves were pretty important then for a start, so I've got a lot of catching up to do. I think your channel is just what I need, thank you.
i saw an ultra bright LED flashlight video on UA-cam... Can you (or are you going to? if yes, then when?) make some CRAZY things that we can do with electrical components (as a series)? Like, the ultra capacitors was pretty CRAZY, it would be fun to know how a simple component we use, can do on a super saiyan mode.
This guy has really a talent for explaining things! Thanks
Great to see you back.
Good to have you back!! Been waiting for your videos!!
I hope you finally come back and i don't need to wait 3-6m for a video :( i really like your channel. This channel help me a lot with my electronics projects :D Thank you @Afrotechmods
3:47 : magic smoke !
It seems there is a clicking sound (relay?) coming from the powersupply at some point while it is switching between constant current and constant voltage modes. Seems it still limit current somehow (to protect itself?)
A simple and clear explanation. genius 👍👍👍👍👍😊
very clear explanation & easy-to-understand demonstration.
BeSt presentation ever. No fidgeting fingers, No hem/haw or senseless drone..No.. off topic chitter chatter. Just that FaCTS !
The voltage for led lights is dependent on what light they are built to emit. Take 1240/wavelength of light emitted to get the eV. eV are called electron volts for a reason since they are for every electron that gets excited in the LED, it emits a photon and best does so at that voltage due to the bandgap energy of the piece of semiconductor inside the LED. High voltage will overheat the light when so many electrons going through very quickly just like anything that short circuits and overheats.
Being an electrical engineer and hobbyist I could smell the burning led in my mind when you fried it.
Nice to see you back
LED 101: High Current = Bang!
Seriously awesome tutorial. Exceptional content for such a short video. Just subscribed.
Happy ! Such a resourceful channel has got life.
this might be a dumb question, but how come in this video at 4:40, i see you have your resistor installed on the cathode to the black lead to your PSU? but in your NEXT video following this about resistors, you are adding the resistor to the red anode side of the circuit? does it not matter where you place your resistor?
I once bought a couple of larger UV LEDs to build a UV flashlight but the shop i bought them from did not have any data on them. Is it possible to find out the forward voltage with only a basic multimeter without destroying one of the LEDs? Or do i have to look around for something that looks similar and hope for the best?
Thanks for the informative videos!
Yes, it's very easy. Put a 1k or so resistor in series with the LED and power it up. Then use your multimeter set to measure DC voltage, and measure the voltage across the LED. That's the forward voltage!
Afrotechmods Thank, that sounds easy enough. I tried googling around for this answer a few times but found nothing.
Thank you very much!
excellent video!!! like always xD thanks. saludos
Hi Gastón :)
Proyectos LED
There are Three ways to tell the cathode from the anode: the two you mention and looking inside the clear plastic: the *Cup-shaped* side is the *Cathode* side. C = Cathode
If you don't know the forward voltage of your LED, use a power supply which has a constant current mode and can display voltage and current. Turn up the voltage until your LED draws 20mA. The voltage is your forward voltage. Use that to calculate a suitable resistor. Not all LEDs run well with 20mA. The high power ones generally run with 300-700mA. They get really hot, so don't forget the heatsink.
The normal abbreviation for cathode is K, not C. Yes, you might have seen the latter, but it's not the norm.
Make sure to explain how LEDs have a non - linear IV curve in the resistance video.
Maybe a section on bandgap, doping etc?
best tutorials and explanations yet keep them coming.....
OMG!!! Best videos I’ve ever seen regarding this subject. So informative, comprehendable, and easy to understand, I even took notes!!! Thank you so much for these!! Subscribing!!
Great video, Are there DIY kits out there to do your own LED boards for projects such as side marker lights, signal, and tail lights for older cars?
awesome video as always !
for me i usually know the cathode from the anode is by the metal area inside the plastic
the cathode is bigger we usually say "the flag side is the cathode"
sorry for my bad english
glad to see you back at it, thanks.
so if you were running, say, a bunch of LEDs in series, do you need a resistor for every LED or just one resistor for all of them?
Happy that Afrotechmods is Active on youtube again! \m/
Thanks, please do more basic tutorials.
welcome back afro!
I like how you explain and illustrate the topics.
Subscribed!
good video. It was so illuminating
I saw the light.
thanks this video help me a lot. Now i can finish my project.......
Confused on one thing, prior video you explained how electron flow is actually negative to positive but in this one you say the anode is suppose to connect to positive side and the flow of electrons go from anode to cathode, which is backwards from other video. Am I missing something?
Very Nice
I recall, back in the late 70s, red LEDs were available, though very expensive. They glowed, rather than shined. In 1980, I bought a pack of 50 once, for a light chaser project. They cost quite a bit. I never did complete that project and that pack is still around somewhere.
Then came green LEDs and suddenly the technology was interesting. Blue were first announced in a Dutch magazine called Electra. TVs screens couldn't be that far behind.
I remember LED numerical readout display on hand calculators back in the 1970's!
Yes, and on watches where a button had to be pressed to make the display light for a few seconds.
The first kid in my school that had one... you read 4 digits then you had to press a button to read the next 4 - that is how expensive they were then!
Hi, Fist of all, i liked the way you presented the concepts.
very clear, simple and to the point. Very nice.
Secondly, I was trying to check the next video on Resistor, but am not able to find it on your channel. can u share the link plz?
thanx brorher its shed yet more light on things we take for granted.no pun intended
You can also show how junction temperature change impacts performance when driving an LED with Voltage and ballasting with a resistor.
Better to drive using a constant current source, but this is not cost effective commercially.
seriously why somebody thumbs down this?? WHY? It does exactly what title say in best way possible...
Great video! Short and straight to the point. I thought the 9V battery trick was interesting.
love this 101 LED tutorial . Question . I have a winding path thru the woods of around 1,000 ft long.
I would like to string some LEDs above it for indicating the path at night ..like lights on the floor of an aircraft for emergency exit. There is no 120 AC volts at that location so I was wondering how to do it with solar . Now , I see solar being used on electric cattle fences emitting DC power. One wire carries current in a pulsating manner and is grounded at the other end . Can I use such a system , trough a DC batt. by connecting one wire to the anode and run a seperate wire to ground ?
Thank for the video.
Basic information is the place to start with. Looking forward to more videos from you.
I thought you were going to get into how a LED works. Thanks for the video, I did learn something.
Thanks for blowing up those LEDs without the current limiter ... saves me from having to demonstrate this myself to my students and burning out my own LEDs! 😆👍
I will eagerly awaiting the next video installment. I'm very interested in making some simple LED system and it's power supply.
This was so helpful....
It helped in my science project
Thanks a lot for your explanation
Where did you find the table of voltages of the different LED's? I find it peculiar that the blue and white LED are not said to have the same Vf - After all a white LED is just a deep blue (royal blue) LED with phosphor on top, so the Vf should be (and is generally, apart from small differences in chemistry) the same.
The respective LED datashit has that information. For example here:
www1.futureelectronics.com/doc/EVERLIGHT%C2%A0/334-15__T1C1-4WYA.pdf
Go to the fourd page, there is a table that says: "forward voltage", and there the min. voltaje is 3.0v and the max. voltaje is 3.6v
Almost all generic LED's have the same forward voltage because they are made with the same material.
Red, orange, yellow, and 570 nM green usually have a a fV of around 2 volts while 525 nM green, blue, and white around 3 volts. IR LEDs are around 1.6 volts. Read the data sheets and uses these numbers only as a guide if there is no data available. Current is another story, a data sheet is required. Most 3mm (T1) or 5mm (T1-3/4) have a rating of 20mA as do the smaller SMT packages. The data sheets are important especially once larger packages and wattage ratings of LEDs are used.
A white LED is in fact a blue LED with phosphor on the lens. A manufacturer may have blue and white LEDs that use the same die and have the same voltage and current ratings. The same can occur with white LEDs of different temperatures. Warm white (2700 - 3500K) usually have a lesser light output as the phosphor is thicker and of a different composition than that of a neutral (4000-5000K) or cool white (5000-6500K) LED. The same die may be used to produce white LEDs of all of the different color temperatures. The color of the phosphor on a warm white LED has a visible reddish tint and tends to block more light than that of neutral or cool white LEDs and lessens the light output..
One should also be aware that some coloured (red, yellow, orange, green etc) LEDs are actually using the same technique as white LEDS - using a blue LED internally and using phosphors to generate the visible colored light. For these the usual rule of varying forward voltage by colour doesn't apply.
For instance used in some simple Christmas/fairy light strings where all the LEDs are wired in parallel and all run at the same voltage without needing resistors to adjust for varying forward voltages
And if you're buying LEDs from China (eBay, AliEDxpress et al) sometimes batches have the pins reversed (ie the long one isn't the anode). They can even have the semiconductor chip reversed inside, so not even which leg that is connected to the 'anvil' (the larger internal piece of metal) is a sure thing. Never assume - test.
Simply awesome videos on electronics. Really well explained and easy to understand.
I love the flattened edge. So from above it looks like a C and the flat side is the Cathode, And the long wire is the Anode.