I would just like to say.....that was the most simple way of explaining the triangle....when I was at trade school doing my electrical apprenticeship...at the start the way this was explained was so SUPER CONFUSING MY HEAD WAS GOING TO EXPLODE...🤯 SO HATS OF TO YOU ON A SIMPLE WAY OF SHOWING A WAY THIS ALL WORKS....I WISH I COULD HAVE BEEN SHOWN THIS BACK IN THE DAY....WELL DONE...👍
Bought some 5050 SMD LED's for a project and this was valuable information. Never really got into RGB's that much so I'm learning from videos like this. Thanks for the info, you helped me more than you know.
Hey, youre so nice and teaching this as simple as possible and taking it slow... it ecourages me, a commoner, to study this. I always thought I would never get it, but now I actually do. Thank you Sir
Never have been in any electronics class in my life, you made this very easy. I can say, I just got my first crash course... Thank you sir... I love messing around with electronics, yes did made some messes before, but am still here... 😂😂😂
I would say that everything is right with this video, except for two objections. An LED which is rated at 20mA, does not positively need to be run at 20mA. They look just fine with only 10mA flowing through them, unless you want to be able to see their state in full sunlight. It's a benefit of modern technology, that they can make LEDs so bright. And so, I have often put resistors which exceed the values you calculated here, knowing that this will cause less current to flow. Further, on rare occasions I've had to change the operating voltage of a circuit, which contained no analog sub-circuit except for the LED's. And in cases like that, it would also have been inconvenient to have to change the resistor on each LED. So, if a maximum supply voltage of 12V is to be tolerated, I can also just say over the cuff, that a 1kΩ resistor will be 'safe'. It's just that the LED will seem a bit dull / half-bright. Given the same, single blue LED as you did show, a 500Ω resistor will come close to producing 20mA, because 12V < 13.2V.
Splendid, simple instruction. Much appreciated! If I have a higher voltage source, say 12v, will a larger resistor mitigate the potential burn out? Ah! You’re well ahead of me.
Beautiful job explaining how to determine resistive voltage drop requirements on how to drive a led. Great job on identifying units in the equations. I think the video could have been better if you explained the equations used to get wattage. Like P=VxI and the other equation variants.
I went through an Air Force tech school back in 1976. I understand everything you explained. Well done. But, I've gotten a little rusty over the years. One day I got a phone call from my son who worked at Circuit City as an installer of various electronics. He had a question which made me re-think a simple series circuit. He had an LED that runs on 5 volts that he needed to install into the 12 volt car. That meant he needed to drop 7 volts across a series resistor. However, we were lacking the important information about current. He looked on the packaging of the diode and it provided the specific milliamps needed. That allowed me to determine the correct resistance to put in series with the LED. While we were still on the phone, he hooked up the circuit. Bingo! LED was on and nothing was burning. It felt good to know that my brain can still work through simple electronics when necessary.
Content is king, why don’t you do a step by step build a synth series? A CS-80 using modern components may seem ambitious, but something like an SY-1 would be interesting. Then people could make multiple examples of that mono synth for a poly synth variant. Should give you around two years of content. And then you’d have loads of The Fuller Luv Philtre synths out there. You could also get sponsorship from some parts source outlet where people can get their parts from. A win, win.
Great and very useful video, a whole series of basic electronics, how too videos wouldn’t go amiss. Maybe you could do a step by step, build a synth tutorial. A CS-80 using modern components may seem ambitious, but don’t let that stop you, or something like an SY-1, a mono synth that someone could use multiple example’s of to make a poly synth.
Vary good video. I learned more from your video on LED circuits then other videos I have watched. I was hoping to see more electronics videos but found they're mostly musical instruments.
Very well explained. One step up would be to put a bypass restor around a different colour led to balance up the current. To help confirm the understanding.
Great video, Markus. 😃🙏🏼 I specially like the triangle. When I got familiar with that at school I used it at many formulas. 😉👍🏼 I only have one critic to say... Don't put the dot (comma) in the middle of the numbers! Then it can be mistaken for the multiplication sign and is very annoying. 🙈😉
Really good tutorial. I like to use a multimeter to find the Anode and the Cathode of a LED. Put your multi-meter in Diode mode. Connect the lead one direction the diode doen't light and the meter will measure "OL". Connect the leads the oppiste direction and the diode lights (a little dim).
OK, confusing point at 4:50. It looks like the second LED turns on before the power is connected! In fact the first LED is shining through the second LED. It probably _did not_ look like that to Markus's naked eye, but eyes are far better than cameras at handling a wide range of brightness. Incidentally, I'm surprised we didn't see the infra-red LED light up, because the classic way to tell if an IR LED is working is to look at it with a camera. I just tried a DSLR and a webcam - both can see a TV remote's IR LED.
That was very well explained. However, I think it might have been better for a new person interested to have broke the video into different parts. This is good, but I think it would have been even better if you had started by explaining how a Project Veroboard/Test Veroboard works and is connected up internally. This would allow a newbie to get a board and connect it up to try it. There is nothing like getting a small kit and connecting things up to see it work for yourself. It might be worth making up kits, or getting someone to make up kits, so this can be done easily. Small bags with labelled components in them, just to cover the projects as you go. Also, a little instruction leaflet would help those starting in electronics as well, just to go with the project you are doing at the time. Just a thought. If people would be interested in this, then they should comment. Sometimes, just working it out, then putting it into practice is by fat the best way to learn.
I memorized the two basic formulas that make up the power wheel conversion chart. I call it the PIEnEIRs of electricity. P≈IE and E=IR are the two main formulas that can be used with each other to make up the entire 12 formula power wheel.
So... I hope you'll read this at some point. My question is, what are you usubg to power this stuff?I've never done anything like this before but recently got into model building again, and I want to light up my projects. Now, I understand how to choose the correct resistor (Thank you, btw) but how do I choose the actual power source? How do I decide to go with either batteries or something I plug into the wall? Also, are you aware of any sites that sells circuit boards or power sources ready to go? Thanks a bunch!
I install LEDs to replace bulbs in model railroad locomotives. I have found that there is no need to run the full 20 ma. We can drop down to 10 ma and the brightness is very nearly the same as at 20 ma. The LED will probably outlast the locomotive's motor at that ma flow. We can drop to as low as 7 ma and still have acceptable brightness. Another thing to point out, red, green, blue, and white LEDs each have a different voltage rating, though for the sizes you show they are all usually 20 ma. My point, use the results of the calculation you show as the minimum resistor value, and go up from there. Try common values that are higher and still give you acceptable brightness for your purposes. White LEDs are available in "pure white", "sunny white", "warm white", etc. Those other whites look more like an incandescent bulb and work well in replacing meter bulbs in vintage stereo and radio gear you may be repairing.
Sorry if I missed something but we changed the resistor max watt because using the same resistor as in the series would meant overheating risk. You said switching to the higher watt rated resistor is less efficient, but required right? Again sorry if I missed a vital part of your demo. Great video 👍🙏
That does refresh my memory thanks. One little thing, I remember in the electronics school I went to they taught the electron flow method; that electricity flows from Negative to Positive.
Awesome explanation sir! Very informative, and taught in a way that the layman can understand. Very new to this, so please forgive me, but in regards to the wattage of the resistor, is there a disadvantage of just using one with a high enough rating other than its size? Lets say your project only required 1/4 watt, would there be any disadvantages in using a 1 watt resistor?
How did the second LED light up before you completed the circuit with the 100 ohm resistor? Generally, you shouldn't drive any component higher than its rated current.
LOL, I wondered that until I realised the first LED is shining _through_ the second LED. If Markus has realised how bad it would look on camera, he'd probably have put them further apart.
When people were trying to figure out current direction, it was a just a guess with a 50 percent chance of getting it right. Science has proven that they got if wrong. When I was learning electronics I was taught that current flow is from negative to positive. Why people want to use something wrong is beyond me.
well its trial and error, I just use a variable power supply and slowly bring up the voltage to get the led lit up and try and take measurements of what current is being drawn by the led.
It's not just a matter of choice to say "I would go with a higher resistance". You *must* go with a higher resistance, or you risk burning out your LED. That "20mA" number from the datasheet is the *maximum allowed current* you are guaranteed to be able to use *without frying the LED.* That means the "90 ohm" resistance that that calculation produces is the *minimum allowed resistance* which will keep the LED alive. If you go below that and use an 82 ohm resistor instead, the LED will be experiencing 22mA of current, which is *10% over its absolute maximum rating.* Yes, many LEDs will work (for a while) over that limit, but there's absolutely no guarantee of how long they'll last that way, and many of them will just fail after a fairly short time. In general, it is good practice to use a resistance slightly higher than that absolute minimum number anyway, because you never know whether the supply voltage is going to be maybe actually a bit higher than 5 volts, or the resistor value (which for cheaper rated resistors can be +/- 10%) isn't exactly what it says it is on the package, etc. *Rule of thumb: Take the number from the equation and **_add 10% to it_** before then finding the nearest value resistor you can.* So in this case, the equation says 90, you add 10% and you get 99, so a 100 ohm resistor is actually _the correct value._ For things which you know are going to be on a lot for a long time, it's better to add 20% or 30% even. As was mentioned, LEDs running at 80% or so of their max current are, practically speaking, almost as bright anyway, and will be much more reliable in long-term operation.
Interesting video, thank you. Thinking about the parallel placement of the diodes, does that then mean you could take the circuit power supply back down to 5V? It would mean you only need 45 ohms resistance and 0.072w, so a 0.25W resistor would be suitable again, right?
If you place the diodes in parallel, then each one must have its own current limiting resistor. It's fine to use a 5V supply and a 100 ohm 1/4 Watt resistor with each LED.
Howdy, Brother! What resistor should I use if I have a yellow 10mm LED Emitting Diode (1.8-2.2V) powered by two AA Batteries (on/off switch in the loop)? I'm not even sure if I asked the question properly 🤠. Thanks for any assistance.
This doesn't make sense to me. Why would Volts divided by Amps of an LED give you the resistance of some other component not yet in the circuit? I would have expected it to give you the resistance of the LED itself. The LEDs I have don't even list their Amperage (probably because they've got a voltage range) but they have 3 Ohms listed against all of them - now I don't know whether this is the resistance of the LED or not. I don't see how it could be the resistance of anything else given it doesn't know what's going to be connected to it as a power source.
In answer to your first paragraph, what you are calculating is the value of the series resistor to prevent excess current flowing through the LED. The author has said that he wanted 20mA current through the device ( this may be correct for the coloured LEDs but is far too high for the standard red ones) by subtracting the voltage needed to 'strike' the LED you arrive at the figure of voltage across the series resistor - it is this that is calculated by dividing the voltage across it by the current in the circuit. It's misleading to think of LEDs as having resistance....if you look at the way I used a rule-of-thumb to 'estimate' the value of the series resistor (in my earlier post), I ignore the LED - for supply voltages above 12v - and calculate the series resistor by using the supply voltage divided by the circuit current....this is near-enough approximation for most practical purposes - for indicator applications it's better to 'underrun' the device as it last longer....especially the earlier ones (all red!) when I worked in electronics
I liked this video up until the power source was increased to 12V when two LEDs were put in series. Certainly, the video's presented option on raising the supply voltage is one way to skin the proverbial cat, but I has assumed that after that option was presented, the parallel LED option would be presented as a (probably) better solution, keeping the 5V supply voltage. Eventually, the video got around to the parallel LEDs, but kept the 12V supply. While it is not always an option, combining multiple LEDs in series or parallel can be driven by whatever works best for the available supply voltage. Of course, this then needs to be balanced with him much current the supply can furnish, and that might tip the series or parallel question back the other way. Something else that would have been nice to have in the video: It is not good practice to parallel LEDs without giving each its own current limiting resistor. A lot of inexpensive LEDs are fairly loose in their tolerances, so simple paralleling with a single resistor can often have visibly noticeable different brightness.
Cool video, I have recently gotten into building/ modding guitar pedals and part of that entails adding LEDs...this definitely helps break down that process so I can understand it. Is there a breadboard you would recommend to get started with?
Hi Tommysea9000 I just have a few odd breadboards that I have had for many years but you can pick them up cheaply on amazon and they should be fine. best wishes
W/O a data sheet. You need to use a power supply that you can vary the voltage while monitoring the current draw... When the LED glows, use the lowest voltage/current that will make the LED glow properly. Then calculate the correct resistor. Simple
Interesting at for years I always paired a single LED with 5V with 470 ohm in series and a 12V with 1K in series. Recently I had a project that the LEDS seemed way overdriven and I had to use 10k 1/4 watt resistors with the LEDS to not over drive them with 12VDC. Only thing I can think of is that the new LEDS have much lower mA needs and so the 10k resistors are needed to extend the life of them. Verified with multimeter that resistors were in fact 10k, I was so surprised as back 30 years ago it was 470 ohms for 5 volt supply and 1k for single LED lit with 12V supply voltage. Additionally the RED and GREEN and YELLOW LEDs have different current draw than the BLUE and WHITE that use less current. These newer LEDs must be way more efficient than those LEDs from 30 years ago.
Modern LEDs are often made using different materials from years ago and are generally much more efficient. I can clearly see an "ultrabright" white LED illuminate (dimly) with just a few microamps passing through it.
@@RexxSchneider I was surprised an UB LED was lit at just 1 mA - it served well enough as an indicator. Did not try lower current - in my experience with normal LEDs the brightness drops off quickly
@@kennmossman8701 I'm looking at a white "ultra-bright" passing 20mA right now. It is very bright, far more than you need for an indicator. At 1mA, it's still bright and perfectly bright enough for an indicator. At 100μA, it's dimmer but clearly lit, and looked at head-on would still be usable as an indicator. At 10μA it's rather dim but still lit. With a 5V supply and a 1MΩ series resistor, it's passing about 2.5μA and is glowing dimly. The efficiency of these is amazing compared to a couple of decades ago. For what it's worth, the forward voltage of the diode is 2.5V at 2.5μA, and about 3V at 20mA.
Hello I need help. I am installing an led switch on my guitar with current rating 5amps and 12v. I am connecting the switch to a 9v battery. What size resistor do I need?
Thank you so much! But how can I calculate the maximum power of a resistor? I have desoldered a lot of old circuits, but there are no inscriptions on them except of color stripes indicating resistance. Knowing the resistance, is it possible to somehow calculate the maximum power?
Not really. You have to either buy resistors with a particular rating and remember what they are, or learn by experience roughly how big a resistor is when it's rated for 1/8W, 1/4W, 1/2W, 1W, etc. The other option is to pass a known current through it and see how hot it gets. If it's too hot to touch, you've probably reached its maximum power rating! If it's any help, start by assuming it's at least 1/4W (unless it's really tiny) and test with a current that would give 1/4W using P = I*I*R.
Just to point out that you don't have to drive an LED at its rated current. Todays LEDs are a lot brighter than the ones we used to have. I'll often calculate a resistor as in the video, double it, and still think the LED is way too bright.
Brilliant video, now what about helping slot car guys with lights in the cars What value of resistor will be needed for a variable supply from say 3.2 volts upto 12 volts as this is generally the maximum voltage going to the car, understanding they want max benefit of the lighting, consider that fitting a lm7805 is just not practical and requires more soldering and securing, would they connect in series or parallel You valuable experience will be greatly appreciated
I have a question, I have a simple 5v usb cord powering a 3.5v LED... it's a bit too bright, so I added a resistor, bringing it to 3.5v (checked with meter)... I add the LED after resistor, it doesn't work.. I check again with the multimeter, it says 3.5 volts (after the resistor)... I add the LED to the circuit, after the resistor, again, it doesn't work, .. what's going on? why is it not lighting up? -The resistor is: (light)green blue red gold ...
I usually take a look in the parts bin and then calculate how much time I am going to spend on this. More often then not the first pick is good enough.
Great video. I have a couple small car electrical projects where I wanted to use LED diodes and just didn't know how to properly put them in the circuit. It seemed so difficult to learn, but you broke it down easy to understand.
Am i the only person in the world who's tried running LEDs in parallel and only had one pull all the current and not understood why, or how to fix it? I wish channels like these would go into some common beginner mistakes and pitfalls and rectify them.
Thanks for uploading! So in the last example i could also have taken TWO 110 Ohm resistors and the wattage would be ok again? 2.) Two different LEDs ask for two different resistors in two parallel strings?
I like the way this is explained but I have some issues with it. First of all it isn't always clear what the voltage of the LED is. Much (or Most) of the LED's are produced in China. I often bought them because they are cheap. However the technical details were often wrong. Sometimes LED's that should have been lighting up at a specific voltage level, say 3,1 V already light up at 2,3 V. So I would recommend to establish the correct voltage level. This is very easily establisht. You just have to use a power supply with delivers a voltage level between 2 and 12 V. You can use a adjustable transformer for instance from a trainset or you use a battery (minimum voltage level 3V but preferable a 4,5 V type). Then you have to have a potentiometer (or a adjustable resister) with a range between 0-1000 Ohms. With the adjustable transformer you could increase the voltage level until the LED ignites which gives you an indication. The other method with the potentiometer is a bit more accurat. After the LED has ignited you can measure the resistance of the potentiometer. The other issue I have is the series connection of LED's on a power supply with a lower voltage level as is required. In those cases it would be possible to connect the LED's parallel. However that means every LED would need its own resister.
Yes, every LED should have its own resistor if they are in parallel. Red LEDs have a voltage drop of about 2V and blue ones about 4V. As a rule of thumb. current of 30-50 mA will light most of them up. Subtract the voltage drop and divide by the current as recommended on the datasheet. So for a 12V DC supply, a resistor of 200-330 ohms will suffice. For a blue LED, 160-260 Ohms.
Lightning makes much more sense when considered as sucking electrons. Same with the collapse of electrolyte in capacitors. The famous "easiest path" doesn't have to be sought-out by the discharge, the weakest points simply relinquish their electrons first.
@@PracticalCat when you understand what AC does to current then this whole notion of electron flow verses conventional flow becomes a complete NON issue. Can you trace the current path on the schematic at hand? This is what matters most in life ...
That was a typo. I actually was scanning the comments to see if anyone had noticed (and then promptly forgot... until I saw your comment). ALL previous examples (all examples except the last one) are series. The last example is parallel. Good catch though :)
Let's say I connect 2 leds in parallel to a 5v power supply then what is the value of a resistor i need to connect to make sure that my circuit works safe.
Those are called breadboards for electronics. you should be able to find them on amazon or any good electronics reseller, they come in many different sizes and are very useful for trying out circuits.
Hi, great video thanks. Question, I have 5 sets of twin green LEDs with forward voltage of 2.7v so believe from the standard 5v arduino mega source, even without a resister, they wont light up. Correct?
Hi Mark. im completely new to synths. I have been looking at the early days of analog synths - i'm not bothered about the various electronic modules - there's tons of documentation on those. what i cant seem to find is how the analogue keyboards were built. i have ETI 1978 on the Transcendent 2000 Synth. but the keyboard was a module and the design of the switch contacts is not shown. I saw one of your uploads which showed an analogue keyboard shot, i think it was one of the Moog perhaps the voyager? Sorry i cant remember which. I think it time the keyboard design and switching and resistor section was covered in more detail I'm sure this would be popular. I'm asking here, as you cover stuff in great detail and that's whats required. I for one would like to see the inner workings... Sadly i don't have resources to satisfy my curiosity. Hope its of some interest to you as a future topic.
Hello. yes its is a good thing that would make an interesting video as there are so many different ways these keyboards work. some woth switches some with rubber connectors some with springy metal contacts. i can think of at least 5 maybe 6 already. trouble is there are no carboot sales for me to buy these things as this lockdown has put my collecting of things on a temporary halt but hopefully we will get back to normal again one day. stay safe best wishes.
@@markusfuller Hi Mark Look forward to your keyboard design upload. I inherited an electric organ from the 1980's don't know the make, can't see any markings other than Star Strings. i just looked inside the keyboard it has metal leaf contacts so i assume the early stuff was all individual leaf type contacts? I've been looking for a cheap as hell keyboard too - i want to start trying out simple sound circuits while i wait. it looks like an addictive and expensive hobby.. will have to put limits on it.
say you have a 5V power supply, connect a LED and a 200 Ohm resistor as done here, Use a multi-meter (20 VDC setting) and measure the voltage across the LED - that gives the Vf
Great video! 🙏🏽 The drawing of the inside of the LED (the “cup” and the “hand”) looks like someone’s spiking a drink in a “salt bae” pose! #thebillcosby
