In this video, the author showcases several types of power inductors, including simple copper wire wrapped around a ferromagnetic core and SMD versions that are more difficult to identify due to their compact size. The author notes that these inductors are commonly used in power supplies, but may not be as well-suited for other applications.

One type of inductor being featured is the color ring inductor, which looks similar to a resistor but is actually an inductor. These inductors have been laying around in the author's workshop for 10 years, and despite their long history, they were not used until now due to a lack of understanding about their limitations.

The author sets out to test the color ring inductors in a power supply circuit, using a boost converter as a starting point. They first replace the original inductor with a new one from the boost converter, and are surprised to find that the system still works despite being able to draw more current than it was originally capable of.

To understand why this is the case, the author turns to the theory of how inductors work. An inductor stores energy in its magnetic field and releases it as the current flows through the coil. However, an inductor also has a saturation current, which is the maximum amount of current that can flow through the coil before it becomes damaged.

The author notes that measuring the saturation current with an LCR meter is not possible, so they develop their own test circuit to measure this value. The test circuit uses a MOSFET that can open or close its path depending on the voltage signal created by a function generator, which allows them to vary the duration of the pulse and observe the current flow through the inductor.

As the author increases the duration of the pulse, they observe how the current through the inductor rises almost linearly at first, but eventually becomes exponential. This is when the saturation current is reached, and the inductance decreases. The author notes that this value is important to understand, as it determines the maximum amount of current that can be drawn from an inductor.

The author then tests one of the color ring inductors for its saturation current, using their own test circuit. They find that the saturation current is around 400mV for a 22uh inductor, which is much higher than they expected. This means that the inductor can handle more current than it was originally designed to.

Despite these findings, the author notes that color ring inductors are not suitable for high-power applications due to their low saturation current and decreasing performance when hot. However, they do find them to be perfect for low-power applications such as power supplies, oscillators, and signal filters.

The author concludes by saying that they were wrong to ignore these color ring inductors for so long, but are now happy to have understood what they can do and their limitations. They also note that it took a lot of digging through the internet to find a datasheet with more information about the coils' electrical properties, which is still missing.

In conclusion, this video provides a detailed overview of color ring inductors and their performance in various applications. The author demonstrates how these inductors can be used for low-power applications, but notes that they are not suitable for high-power applications due to their limitations.

WEBVTTKind: captionsLanguage: enOH BOY!Now this is a power inductor, super easy toidentify since it is simply copper wire wrappedaround a ferromagnetic core and you oftensee them in more beefy power supplies.Then you also got the SMD version of themwhich are a bit harder to identify; but onthe inside still the same deal, and you seethem all the time on smaller power supplies.And then you got these things right here whichlook a bit like resistor, but are in factso called color ring inductors; meaning yes,they are also inductors like the other twobefore.I've had these things laying around for 10years now because when I started with electronics,I simply searched for coils and inductorsand found these; which are still to this datenot only way cheaper than other inductor types,but they also have tons of 5 star reviewsand are also nicely labeled for easy usage.So why haven't I used them before?Maybe they are useful?Well, we will find out in this video becauseI will be pushing them to their limit so thatyou can decide whether you want to get someas well or also ignore them like I did.Let's get started!This video is sponsored by Particle and theirnew Photon 2 development board that I immediatelyused after receiving it, to pull off a smallmini project.You see, the problem with the battery packfor my mini solar system is that I am notconstantly monitoring the voltage of eachbattery and thus they could drift apart overtime.So to fix that I simply created a perfboardwith additional parts for the Photon 2 whichis quite a powerful and fast microcontrollersystem that has 3MB of RAM and supports BLEand even Wi-Fi with 5GHz.Particle's new Asset OTA feature also makesit easy to include bundled assets, allowingyou to flash multiple components within agiven system.So once I hooked up the perfboard to my batteriesand powered the Photon 2, it was simple toprogram and upload code wireless using ParticleWorkbench—no computer connection needed.And as you can see with the help of ParticlesIoT platform, I can now check the batteryvoltages whenever I want through the powerof the internet.Interested?Then check out the link below and use codeGREATSCOTT20 for a 20% discount.Now first off, let's do some destruction andhave a look inside these color ring inductors.And as you would expect there is nothing magicalinside; it is once again a copper wire wrappedaround a ferromagnetic material.And I got to say that I kind of like the colorrings because this way you can easily tellwhat inductor value we are working with.Now of course SMD inductors are even betterby directly telling you their value.But when it comes to bigger coils, then youreally need something like an LCR meter toeasily determine the inductance.But then again the big plus point of prettymuch every inductor type, except the colorring ones, is that they come with a properdatasheet where you can find the most importantelectrical specifications.And sadly when ordering such a color ringinductor assortment kit, you normally notget many details about them.For example; this product description onlytells us all the inductance values we getand that they can handle 1W of power.And I especially love their material choice.But jokes aside; last but not least the descriptiontells us that these inductors can be apparentlyused for every application imaginable, lovely.So yeah the power rating is pretty much theonly information we get which is by the waysuch a useless information that no other inductordatasheet mentions it.I mean it is nice to know that these inductorsreach a temperature of 150 degree Celsiusat 1W and are not flammable when pushing thembeyond that; but it would have been way nicerto know the more important electrical parameters.But before getting too lost in the theoryhere, let's do a practical experiment withthis little boost converter power supply herethat like the name implies takes a lower DCvoltage and boosts it to a higher one.And when hooking it up to a constant loadthen we can easily find out that at a currentdraw of around 1A, the output voltage breaksdown a bit.And when observing that voltage with an oscilloscopethen we can see that the noise is gettinga bit out of hand at this point.So 1A of output current is to beat and ourcolor ring inductor with a value of 22uH shouldbe able to do that, right?I mean the boost converters inductor is also22uh; so what's the big difference?Well, after simply replacing it we can powerthe converter like before and notice thata) nothing exploded and b) that it still seemsto work just fine.And I was even a bit surprised that drawingcurrent was possible at all; but this newsystem quickly reached its limit at a maximumof 0.5A at which point the voltage broke downquite a bit and we got tons of noise.So in conclusion this inductor can do halfthe current of the original one and the reasonsfor that is that the job of an inductor insuch a circuit is to store energy in its magneticfield and then release it again while simultaneouslyhindering the current flow.Now the energy an inductor can store equalsinductance divided by two multiplied by thecurrent squared and here we can already seethat it is not all about the inductance valuewhich you can get with tons of different sizedcoils.It is also about the current and for thatyou normally got the saturation current mentionedin the datasheet of good coils which is ofcourse missing with our budget inductor.Now sadly measuring the saturation currentwith an LCR meter is not really possible.So for that I came up with my own crude testcircuit which looks something like this asa schematic.We basically got a MOSFET that can open orclose its path depending on the voltage signalcreated by a function generator.This signal needs to be a quick pulse whoseon time we can vary so that current can flowthrough the coil for only a very short amountof time.Now to see this current flow we got a tinyresistor down here whose voltage we will observewith the oscilloscope because as you mightknow current equals voltage divided by resistance.And with the theory out of the way I put theoriginal inductor from the boost converterin the circuit and started increasing theon time.And here you can see very lovely on the oscilloscopehow the current through the inductor risesalmost linear because that is what inductorsdo; resist the flow of current.But at some point this current flow suddenlydoes no longer increase linear but prettymuch exponential.And this value is called the saturation current;in this case around 400mV so 4A convertedat which point the inductance actually decreasesand thus the inductor no longer behaves likean inductor but more like a resistor; meaningthe flowing current is only limited by itsresistance which is pretty small and thusthe flowing current can get huge.Needless to say this is the moment inductorscan get destroyed as well as your circuit,meaning inductance is definitely importantbut saturation current just as much.So let's try to measure it for the 22uh colorring inductor and yes; it definitely did nottake long to reach saturation at around 160mV,so around 1.6A which is quite a differenceto the other inductor.By the way such saturation is mainly determinedby the core and even worse; when an inductorgets hot this value decreases as well whichis of course what happens near the power maximum;making everything even worse.Now I am not trying to hate on these colorring inductors because as you saw they canbe used for power supplies; as well as oscillatorsor signal filters like the product descriptionclaimed.And when having a closer look at them withan LCR meter, then they perform not that badlyas coils.But what is also 100% noteworthy is that theyare only suited for low power applicationsand I feel like this is what pretty much allproduct descriptions forget to state.That makes them perfect for beginners thoughwho just want to experiment and not lose aton of money if one inductor coincidentallymelts.So yeah it was definitely wrong of me to ignorethem for so long and I am quite happy thatI now understand what they can do and whattheir limitations are.And best news for the end; I dug through theentire internet to find a datasheet that comeswith more of the coils electrical properties;but sadly still without saturation current.With that being said; I hope you enjoyed thisvideo and learned something new.If so consider supporting me through Patreonto keep the show going.Don't forget to like, share, subscribe andhit the notification bar.Stay creative and I will see you next time.