I followed a YouTube Electronics Video and Regret it! (Debunking a 500k video)
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- เผยแพร่เมื่อ 27 เม.ย. 2024
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In this video we will actually be looking at another video on TH-cam. There the creator claimed that you can build a BLDC Motor driver with only 9 components. The catch is that ESCs (which are normally used for driving BLDC motors) consist of way more components and are usually quite complicated. So let's "test" the circuit and find out all the information the original creator kept quiet about. Let's get started!
Thanks to MEL Science for sponsoring this video.
0:00 The "Bad" Video I found
1:53 Intro
2:51 What Information was Missing?
3:37 Building the Circuit
4:11 4 Wire Motor Problem
5:17 First Test (Small Motor)
6:45 Second Test (Bigger Motor)
7:41 Why does the Circuit Suck?
9:21 Verdict - วิทยาศาสตร์และเทคโนโลยี
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Ah stop , these content farm channels are so bad. I watched one guy make a "1000w" amp with almost no components then shows it driving the worst speakers in the world...and barely moving them. Not to mention they never say what voltage it's driven at or what resistance the speakers are but they get millions of views because youtube would rather block a video for a stupid reason rather than a legitimate one!
Sorry to hear that.
@@greatscottlab Why sorry , I really enjoyed you busting their videos. I had a feeling they were rubbish but who am I to argue with like you said half a million views.
The best of those crappy circuits I've ever seen, dunno if it was TH-cam or just some random Internet page, was a power supply.
5V output, some ~5A at most, but you'll need extreme cooling on it, like, some people were adding water cooling to more powerful versions. Why? Oh well it was 7805 based.
Rectify line voltage -> smoothing capacitor -> 7805s (or what is the version that can take line voltage, dunno). That's it. For real, a linear dropping of line voltage down to the supply you want. Not even talking about it not being insulated, so it was horribly inefficient and unsafe at that.
We need a blacklist of videos and channels providing crap and misleading content. Once loaded into appropriate browser extension (that blocks/filters out specific TH-cam videos/channels from appearing), we would all be better off. I already have one started that blocks 40 or 50 of those 5-minute-bovine-excrement channels. For DIYers, this is extra important, to remove time wasters.
One pet peeve of mine are videos with English title and thumbnail, but in an unrelated language and without any subtitles (manual nor generated), which should be a category of its own (given a red border or something?).
A user-contributable github should be created.
@@cbs1710 pretty sure TH-cam sometimes auto-translates video titles. I've seen videos I know have Japanese titles get translated to English on occasion. No idea why it only appears to happen occasionally, but I suspect that's what's happening with those English titles but foreign everything else ones.
Always good to see someone who busts these diy circuits. I'd love to see more of this kinda thing.
I will see what I can do ;-)
I would even be interested in exposing the extremely dangerous electronics projects some of these channels post.
A lot seem to be aimed towards kids, but almost never mention important and deadly aspects. Your knowledge on electronics would be an awesome perspective as I’m not nearly as knowledgeable lol
I do think the video is a good starting point for those who wish to make their own stuff.
I would not call it exactly a bust. It's more too simple to compensate for errors and stalls
@@greatscottlab Can you maybe do a 3phase motor and how to drive those?
Ah yes, this is exactly what happened to me as a kid many years ago, when I found a schematics of a guitar pedal in a magazine, built it myself and decided that electronics is bullshit since it didn't work.
Terrible when something like this is your first experience with electronics.
If you watched the video careful, you would have seen this device DID work.
@@janklas7079 If something "works" doesn't mean it'll keep working in the long run. Those MOSFETs will probably only last an hour before they go poof.
@@greatscottlab I would say this is a pefect first experience. It's simple and it works, but has a lot of room for improvements. A lot of stuff to experiment with.
@@janklas7079 sounds like a great way to burn out a motor.
Nice job indeed Scott!!! Please do not stop making videos where we can learn how electronics circuits works. Congrats and thanks a lot. Regards from Spain.
01:26 a good like to dislike ratio
#youtube please show dislike counter & tag all contents why the reaction
example: I like this because it shows a complicated subject in an easy to understand quality content
Maybe hes using the Return Dislike Button browser extension
they won't as then you'll truly see who is pumping out "mis/dis-information"...which is why they hid it
yeah he must be a fellow return dislike appreciator
also YT removed dislike counter to avoid "bulling the creators" as they said, but it's hided for users and totally showed to the creators...
The only thing hiding it from users does is stop the mindset where people are now prone to bandwagon stuff, lots of dislikes makes them more prone to view things negatively, and more comfortable disliking it themselves.
The problem is, youtubes like system doesn't lend itself to this behavior much naturally at all, and even then the large majority of people won't experience that pressure the vast majority of the time. It's not at all necessary and the only thing I can think of as a benefit is absurdly niche, you'd need content that has a large audience disliking it, and another audience portion in the middle, but also people to acting on a group mindset, and also it actually being detrimental enough to be relevant, which just isn't really common.
Wanting to remove negativity from subjective stuff could be understandable, not everyone will like certain songs for example, and some may actively dislike it. And that can feel discouraging. But even then, it's almost never enough to be a relevant problem, only applies to opinion works, and typically is in the domain of discussion, not like and dislikes. And of course you'd only be influencing people who are going yo actively feel upset that 2% of people dislike something they love, and you probably get the point by now haha.
It's a very strange decision to me. I can think of a few potential benefits like this, but they are so inconsequential and likely rare anyways, that it doesn't really effectively do anything. And on the flip side, you lose that credibility anchor, you lose people being able to dislike misinformation or misleading content. And you lose that feedback for a skeptical mind, you think hm maybe this is good? I mean it has 1k likes. But you don't see the 600 dislikes, so you miss that feedback, that a large chunk felt mislead or disappointed, and instead of just mindlessly clicking the button yourself you are much more likely to use that information to look into and think about things more yourself, had you still had access to it.
Idk man. It's a very strange situation to me, the fact that the given justifications are worse than the junk I can whip up here is even more strange. Whatever. At least it's not something more horrible, like having the dislike ratio hide videos from search or something lol.
The thing with a switching circuit is that you have lots of parasitic effects that you should be really spending time on in the design phase.
It is not only depending on components, but also on the PCB layout and sometimes also the load.
Man I love watching these videos. Takes me back to when I was a kid with little drawers full of components I salvaged from old hair dryers, VCR's, computers etc.
I thought brushless motors were just AC induction motors, and that ESC was just an inverter which creates 3-phase AC...? I think that's what ElectroBOOM said in one of his videos, no?
Yeah and thats... sorta what the circuit in the video does, poorly, a bldc will work with just 3 phases like that but a proper feedback system and all that from a proper controller makes them a lot more useful
It might be a modified sine wave at best or just a rounded off square wave. Real sinusoidal AC takes a lot of components and usually a transformer and filters. Something like an audio amp. Then something like capacitors or a microcontroller to have a 120 degree phase shift for each phase.
Pretty fascinating stuff! Thanks for testing it, dude! 😃
Stay safe and creative there! 🖖😊
Your conclusions are exactly what I always thought of these videos. I started blocking them from my TH-cam as I also got a lot of them and just by looking at them knew that can't be a good design.
Well said!
It's annoying how TH-cam loves recommending fake, clickbait and viral crap more than proper stuff. You gotta really go out of your way to make the proper stuff show up instead.
I wish I could get TH-cam to display only the things I’m interested in and block the rest - I’m so sick and tired of being fed clickbait , reaction videos and fantastic new idea or technology videos 🤢
Great video, I always wanted to test this but I was a bit lazy :))
And I am yet waiting for a follow up video in which you made a VESC esc that blew up but you didn't further investigate the problem.
Thanks. Not sure if I will ever get back to the VESC video. Sorry.
Your video was very helpful, I'm still learning and getting the hang of it still. I'm into House and EDM. I look forward to seeing more of your
I was thinking wow he's crazy holding that motor with a prop on it whilecits running the in the next clip I notice the cuts on his fingers lol 😆 could have been worse!
@GreatScott! Great video, I enjoy your hard work. Would you please consider creating a video showing how to easily modify a the $10 brushless motor controller (like you showed) for higher voltage and current? This seems like a great DIY or buy video! Keep up the good work!
I will give that simple BEC video one tiny bit of credit, although the only reason I can do that is because it exists and caused you to make this explanation video. I had one of those “light bulb” moments watching this. Until now I never understood how speed controllers used induced voltage to time motor control.
Thank you for taking the time to analyze that video. I learned something today.
Great Scott Gadgets is amazing! Your products are helping me learn about signal processing, electronics and so much more. Thanks for all the hard work.
Great video as always! Keep it up
I really love these kinds of debunkings that don't spend half the time ridiculing the thing, but instead go through how it supposedly (or actually) works with all the caveats of why it doesn't work properly. Ridicule is toxic af and I've had to unsubscribe from a certain australian electrical engineer because of it. MORE OBJECTIVE DEBUNKINGS LIKE THIS (if you choose to do more)!! They're always a wonderful learning opportunity when presented as such! :D
Some ridiculing is deserved though especially when the hacks are extremely dangerous, which this one isn't but I have seen to many playing around whit main voltage stuff
@@link7417 Perhaps in some cases, but not when almost the entire airtime of a "debunk" video is just ridicule, especially of an idea that seems pretty good at first when written down on paper but starts to fall apart the moment you squint and start to look into it. At that point, the debunk deserves to be less a ridicule fest and more a "Okay, this is what works in this idea, and this is why this idea as a whole isn't going to work."
@@calyodelphi124 oh I definitely agree whit that,
Interesting concept but I guess there IS A reason they include all those components in commercial ESC’s.
What the fok
How can you comment 9-days ago 😳😳😳, the video is uploaded just now😂😂
@@Xavier_Everwhere patreon
There is. Mostly error conditions and timing. To get timing going, and stuff like braking, one needs a CPU. This increases the number of components a lot. Also, most ESC's also have a BEC function, providing power to receiver/servo's, and so forth.
@@janklas7079 I don't think a CPU is a hard requirement. You could do what the CPU does with comparators etc. But if you did it would be hard to tune and probably only work with one type of motor. Using a microcontroller reduces the amount of components because you move most of the problem from the hardware domain to the software domain.
thanks for checking this out, i have seen many videos about such attempts. It's good to have some one correct them to make sure some one who is a amateur or novice does not get hurt or burn down their own house!
I was waiting for your simple improved solution! 😉
I don't think you totally regretted it. You made another popular video in the process, and we all learned something from it!
True
"It doesn't work _well,_ by any means, but for something that by all accounts shouldn't work at all, the half-baked job it does is quite impressive."
So good to see a proper engineering approach rather than a recipe. Thanks, GreatScott!👍
You are welcome :-)
I struggle to understand, why your English is so good! I wish in England we are taught a secondary language in primary school. The fact you speak English but the second fact you can talk to component level, I’m amazed. 👏🏻👏🏻👏🏻👏🏻👏🏻
I'm actually surprised how well these circuits work
Those amateur circuits ( often 3D fly wired ) are a recipe for learning the wrong way.
Thank you for the information. I wish you success in your careers. Thank you
Great Scott! Love your accent man.
That's a simple astable oscillator. Usually cheap rgb lights use this circuit but they have a cap as well from every drain pin to the next base of the tranzistor. Simple for basic task but not stable for complicated applications
1:24 Ah well, engineers. Ditching the ergonomic office char for a simple wood chair ;)
Haha true :-)
Thank you for this video. Very Helpful.
Great video, keep it up great scott👍
First step to really figure out how BLDC runs is to remember that it's actually a three phase AC motor and the ESC is basically a three phase inverter. And of course, a full bridge PWM controlled inverter with current and voltage sensing will make your three phase motor happy.
PS mad props to Scott for avoiding giving very little clue about it being just a good old three phase system, absolutely love the content.
@MuhammedG Exactly most of those prototype BLDC ccts looks like an amp schematic lmao More Test & Tune is needed to make a pro-compact ESC!
I simmed an "audiophile" 100w amp from a video recently. It had a cool 24% distortion 🙉🙉🤦♂️
So it isn't good as a guitar amp cause not enough distortion, neither as a music amp cause too much.
10/10.
i've been ssing around on a friends soft soft for years, finally bought it. I found your videos and instantly subscribed and have been
Fascinating. I'm a complete amateur at a electronics but love tinkering understanding the underlying principles. In fact 9ne such project a few months ago was to understand how to make a basic BDLC motor driver... before I even knew of ESCs ;)
Ended up using an old Arduino and a bunch of MOSFET modules that worked fairly well, but just as the video would need a manual kick.
My take-away was that while his proved the basic principles it was clearly not a "useful" circuit and certainly not one I'd embarrass myself by committing to TH-cam.
It's a real shame unverified crap like this gets so much attention but I'm grateful that channels like Great Scott are here to debunk and set us straight on such topics.
TH-cam is overflowing with useless videos unfortunately. It seems like a good way to make money from ads apparently, so they won't change it anytime soon. Wasting time is one thing, but there are people who believe such "tutorials" and can get hurt.
The DIY ESC looks to be working on pretty well the same principle as the fancy expensive ones if you break it down. It does not have the same safety and over-voltage/over-current protections that fancy expensive ones have. This would mean it cannot restart when a stall happens, as you demonstrated with the small motor. Purely bench experiment, not something you want to put into production for sure. Interesting to experiment with though :)
The main difference is that the commercial sort have a microcontroller scanning across the coils, activating one at a time. This simple DIY sort is stable just activating one coil, and only switches to another one if the rotor moves. I guess it relies on induced current from the magnets, to switch states.
It would probably be possible to make a better one, with more components, by adding capacitors to turn it into an oscillator with three states - similar to a two transistor, two capacitor oscillator, but with three stages instead of two, with each one triggering the next. You wouldn't be able to adjust the speed easily though.
@@TooSlowTube in this vid it is a joule thief or a skin effect consor
With a few more bipolar transistors you could have actual feedback gating and zero crossing detection, as well as anti-stall kicking. Sure, it’s easiest to do with an MCU if you don’t know a lot of analog building blocks, but those MCUs for the most part implement simple algorithms that come directly from older industrial servo drives that were 100% analog.
@@TooSlowTube I'd love to see that video. Even better if one started with this one, an showed how to solve problems as they turn up. That would be a Great Scott -video I'd watch over and over again.
Hey Scott ! Please make a video on storing electronic components and chargers plugs soldering stuff etc.
aah thank you! i was watching this specific video but before i tried it out and of course regret later your debunking clip showed up
For learning purposes it can be helpful, as it's not as complex for a beginner to understand the concept of a BLDC motor
Hmmmmm well. Fine. I ok with that.
Without going into the math? Is a tad sad but they are way more complicated than one thinks. Salliant poles ect... The math in the control schemes is mad too
@@matthewmaxwell-burton4549 for start your journey you dont want math, you just need see that thing work to start beliving its for you
@@JTKK9 fair point, I guess everyone is different.
@@greatscottlab Starting 25 years ago, for purely teaching purposes, I have been showing the principle of driving a BLDC motor using 3 H-bridge based DC motor drivers. In practice it seems that people who want to drive 3 wire motors already have experience with H-bridges. Many H-bridges don't provide an easy way to control each half independently so I use half of each of three of them.
I first did this with the LEGO Mindstorms RCX (the model introduced in 1996). It made a cool demo and showed useful principles of operation.
The maximum speed was quite slow because the waveform steps were generated with the commands that started, stopped, and set the direction of each motor in the language interpreted by the RCX.
This removed a lot of the confusion about BLDC driver theory and builds on what they already know.
After seeing what amounts to bit banging a motor controller, they see the benefits of a more traditional controller with the 85 parts.
Two sinusoidal signals are sufficient to power such a motor. I used to play, in the form of an experiment, to power such motors from a stereo amplifier to which I fed a stereo signal of variable frequency with a phase shift of 120 °.
Fundamentally, "Brushless DC" motors are just 3 phase motors. The controller is really a 3 phase inverter with smarts to change the speed and handle the different bad things that can happen. Your example would be the same as a phase being out. It "works", but you really need that 3rd phase.
then add 3rd audio channel with correctly shifted signal and itll work. ;) thinking about that sinusial signal and timing logically is some thing ;)
Just then, I only had a stereo amplifier and a generator from the phone application, so I could only get two signals. I was just curious if something like that is possible at all and at what maximum frequency the motors I had will not be able to spin anymore. Everything was checked without load.
Thanks for this video !
Very great video sir, hats off 🙏🙌👏👌
Always a pleasure to see the debunks of these unbearable and dangerous simple circuit videos 🤗😈
There are plenty of them, I think it would make a very good video series
Even though it's not a reliable way to drive a BLDC, I find it's still impressive that it somehow able to spin the motor. I wonder if there is a possibility to overcome the issues you highlighted with this design with few more analog components ( op amps, transistots etc). BLDCs are quite cheap these days yet escs are bloody expensive than the motor. If there is a way to build a simple esc for a lower price, I think this type of controllers too can have some niche applications.
Also I don't agree with the title "debunking". It's certainly a working design, only it's not really good for anything at this stage.
What's the point, you have no control over the torque which esc's give. They allow you to decouple speed and torque which is a godsend.
Considering it doesn't even have a full 3 phase h-bridge, it is rather impressive.
@@matthewmaxwell-burton4549 So you're telling me there isn't another way to control torque without microcontroller esc? I don't believe it. This thing certainly could be improved with right knowledge. Only thing is it won't be a "universal" type esc, rather a "motor specific" once. Still such controllers have some niche applications. And not all motor applications need torque. I.e - The spinning reflector of a laser printer
@@Jtretta Yep, my exact thoughts. Spinning a BLDC is bloody hard, it's impressive such simple design can do that.
First comment which actually makes some sense.
Thank you, that was fascinating.
Great video. You kinda mentioned 3 vs 4 wire bldc motors in passing, a whole video about this would be pretty neat
You catch on really fast, it seems complex but once you learn the basics it pretty much branches into experintation
I kinda still like that circuit, it shows that there are simple principles at work theoretically but you need a more complex system to work out the issues. Wouldn't use it ofc but its good to know that this theoretically is all thats needed to get it to spin.
Well. In that regard I do agree :-)
theoretically you could hold it under a faucet to get it to spin
@@Blox117 How does that matter tho? The question is not "how can I make it spin in general?" the question is "how can I make the motor spin with electricity?". I don't know how your comment factors in that discussion.
Its not like the circuit is not doing what a normal bldc controller wouldn't do, its just that it is quite simple and does it poorly.
@@Ramog1000 you could get it to spin by connecting the phases at different times manually. ta da
Thank you! It helped a lot.
there is also a guys that builds amplifiers witch really look pretty cool engineered, has several hundreds of thousands of viewers, but never shows a schematic and doesn't respond if you ask for schematic.
I needed a simple motor controller, and did indeed build this exact same schematic, at first it was well a joke. I have made several different changes to the 'simple design' which when I have time I will share with you and all should you wish so. It dose do what I finally created and works, though not without the loss of a few FETs and some not so nice words being said. Peace
Would u mind sharing it?
I almost hoped to see some electroboom styled events this time ;)
There were some sparks in the video ;-)
Electroboom doing those for entertainment purposes and intentionally. And he doing well of this.
That cheap control board you suggested is OK for hobby motors but many people need something bigger. For example; many of the treadmills also feature motors that need to be driven in a delta star configuration. Also most modern washers and dryers use three wire motors. Many times the motor driver is built into the control panel board and is very expensive or obsolete. With a cheap after market motor driver these motors could run again with a few basic controls to take place of the dead control boards.
99% of the times I understand nothing of what this man creates in these videos. But I still carry on watching, while feeling majorly dumb. Kudos!
After watching the diagram, I initially thought it works like a crude RING oscillator created by 3 mosfet and 3 coils with a star point. This is awful. Cause not all inductor or mosfets are ideally same and won’t start the motor due to insufficient current draw from star point to Lets say coil 1. It totally depends on high frequency oscillation, so you really don't have much room adjusting the frequency value. Some might add capacitor to control over frequency making the circuit worse and unstable. Also the total load is not equally distributed as you showed in last, it works with star point less motors too - prooving that only two transistor oscillating as multivibrator but in this case creating alternating current due to the nature of inductor to store and pull over the current. last but not least, the freaking spikes will definitely kill a Mosfet in the long run no matter how good they are.
Designer of this circuit must be on weed while designing such bs.
Take 3 of the DIY inverters and feed it by a signal that's delayed by 120 degrees each. Of course, at that point, it's just easier to use a $0.50 cent microcontroller and PWM the signals with a smoothing capacitor. It still won't detect stall conditions, but it will at least drive the thing reliably.
@@arthurmoore9488 absolutely
I think it's more an exercise in "how simple can we make this circuit and still have our functions?" A lesson in building circuits, to be sure, but not something for practical use.
Thing is "simple" is often simple* when you start cutting so much out that the circuit is reliant on certain stray values or other unspecified/variable component characteristics to work properly, which makes it difficult to duplicate. There are some popular simple circuits that are simple and easy to get going with close enough parts, joule thief comes to mind, but there aren't many of them and they don't do anything particularly complicated, e.g. properly drive a BLDC.
Aka muntzing
I follow ALL your videos and they all work! Your channel name has aged like fine wine. GreatScott. Greatest of all the Scotts.
You are amazing, I just switch to soft softs and I am loving everytNice tutorialng about it. It much easier then my last program.
ESCs are so cheap you cannot make your own cost-effective one. It's like making your own op-amps or vacuum tubes, simple and straightforward, just kinda pointless unless your goal is simply to build an ESC.
True :-)
This goes for damn near all electronics.
Unless they are free and abundant if you know where to look.
Hey,
I really enjoy your content.
Do you still take video requests? I'm trying to design a circuit that heats a resistive wire (4 Ohm). Basically I have an Arduino, that I want to use to drive a P-MOSFET that connects the wire to 24V source. Between the Arduino and MOSFET I'm trying to design a totem pole (push-pull) driver but I'm still unsuccessful. I'm trying to control the voltage for the wire, basically trying to do buck converter.
I'm trying to learn everywhere I can but I'm currently stuck with this problem. I don't fully understand the calculation, like how much current is going to the gate of the MOSFET when it's charging and if its charging properly. I saw your videos, but you're using an gate driver IC.
If you would feel like doing something like this with a little calculation I would be greateful.
Thanks and keep up the great work!
The current to the gate of the MOSFET is nearly immaterial. It is a voltage-controlled device. A huge current flows for an instant when switching but then it quiesces (falls essentially to 0). Many will put a resistor in the connection to the gate to keep current down, to keep that huge switching pulse down. Really any resistor will work. 1K, whatever.
You're going to have a lot of trouble running a P-FET to switch that resistor. Specifically to turn the FET off. This is because for the PFET to work you have to put it in the circuit between the resistor and the positive voltage rail with the source connected to the positive rail, the drain to the resistor and the gate toward the Arduino. You cannot put it between the resistor and ground because then the source voltage will drop to 0 when the FET is off, with no constant source voltage you can't manipulate the gate to source (critical turn on/off) voltage properly. you cannot turn the FET around so that the source is at Gnd because then the body diode will conduct all the time and it'll never turn off.
So the PFET will be above the resistor and to turn the FET (resistor) on you simply need to output any voltage below about 23V to the gate. That's easy. The problem is that to turn it off you need to get the gate voltage up to about 24V (above 23.4V). And you can't do that from your Arduino. The highest voltage it can output is 5V (IIRC).
The reason for this is the turn on voltage for a PFET is a negative number referenced to the source. And the source in your case is at 24V since it i. If the turn on voltage is (say) -1.1V you add that to the source voltage of 24V and then that means putting 0-22.9V on the gate turns it on and 23.0V and up turns it off.
Your easiest out for this is just to turn the circuit over and do low side switching with an N-MOSFET. Like in this figure.
en.wikipedia.org/wiki/MOSFET#/media/File:Mosfet_n-ch_circuit.svg
Where you just leave the LED out. And note the source is to ground, the drain to resistor. Other end of resistor to 24V. Then the wire that goes to the switch there from the gate you connect that to your Arduino GPIO. Now to turn off you have to get 0V onto the gate. That's easy, either drive 0V out or just don't drive out and let the resistor pull the gate to Gnd. To turn on you have to get over about 1.1V to the gate. That's easy, just drive out high (5V) and it'll turn on.
Now you can turn your resistor on and off easily from your Arduino. There are some difficulties, like currents. You can work that out. The other is that whether the resistor is on or off it still has at least one end at 24V. So you have to design your enclosure so that that resistor doesn't come into contact with ground OR PEOPLE.
If you can't do that, then you have to go back to the PFET design again and instead design a gate driver. I personally do this by using an NFET to drive the PFET gate. You hook the PFET up above the resistor as mentioned above, put a weak (10K, 100K) resistor from the PFET gate to 24V so that the PFET is off. Now to turn on the PFET you have to pull the gate down. You do that using an NFET. You hook the drain of the NFET to the gate of the PFET. The source of the NFET to ground. And the gate of the NFET to the Arduino. Also hook a resistor to gate of the NFET and to ground. Now, as the NFET explanation above driving the Arduino GPIO out high (5V) will turn on the NFET. But when the NFET turns on now it pulls the PFET gate down and turns that on. Driving out low or not driving out at all will turn it all off, although a bit slower than it turned on (still in tens of milliseconds at most).
Note these NFET circuits (and thus the NFET driver to PFET) will also work fine if you have a 3.3V Arduino (do such things exist?). As long as your gate threshold on the NFET is below 3V. And there are many which are.
i like ur funny words magic man
so are u trying to turn on a resistive wire
or are u trying to make a complementary transistor circuit
or are u trying to make a buck converter?
if bjt doesnt work, u could try cmos
but u dont really need driver for switching a heating wire
if u want to switch something on and off, u don't even need a complementary configuration, normally u only need 1 mosfet
but the tricky thing here is actually the 24v source, most mosfets probably cant handle vgs more than 20v difference
even trickier the that the mosfet is p type
if u wanted a complementary configuration at the gate of the p-mosfet, u would have needed 2 different voltage source that supply high current and more than 2 extra transistors, and the arduino 0v and 5v would have to be mapped to 12v and 24v, this is much more complicated and an opamp might be necessary
a buck converter is quite simple to make, u can feedback using opamp to an oscillation circuit,
or u can directly feedback to microcontroller to control pwm
another way to control voltage for the wire is using linear regulator, lm317 or build ur own with an opamp like the buck converter
building a linear regulator with opamp is easier than building buck converter, just need some resistors and a transistor
but a lot of power loss in the transistor, and linear power transistors are more expensive than switching power transistors
and a buck converter doesn't really "control the voltage", if u truly wanted to control the voltage, u would need the p-mosfet to operate in it's linear region
that's a lot of power loss, most mosfets today are switching mosfets, u can get one expensive beefy switching mosfet and strap a heatsink to it to operate in linear region, but it is still 50% chance that it is gonna burn up in flames and explode because they are just not designed to do that, u have to consider the power lost in the transistor using P=VI
most switching transistors say they could handle crazy currents like 49A 100A, but that's for switching at high frequency, very momentary current, they gonna explode if u tried to conduct 49A in saturation
but why are u even trying to control the voltage?
fun fact, u dont need to
u are just trying to heat up the wire
and why do u care about the current in the gate? for dc application, this is like non existent
only for very high frequency do u actually need to care about the gate capacitance and crap
u are overcomplicating a very simple problem
and there is a very simple solution,
it is called PWM
as for the p-mosfet part, everything is reversed from n-mos
but for both, load are typically driven at the drain side
and source pin are connected directly to ground for an n-mos
this make the mosfet have very low and negligible resistance and voltage drop(see rds(on)), even lower than bjts, bjts normally have 0. something of vce(sat) and vce(sat)>1v for power bjts, but mosfets just has rds(on)
that means when turned on, mosfets are effectively short circuit while bjts are like diodes(in terms of voltage drop)
and p-mosfet has reversed everything, that means current directions and voltages, it can do the same thing as n-mos, just reversed
for p-mosfet, u would want ur source voltage instead of ground on ur source pin
and since positive voltage on gate turns on an n-mos, that means p-mos will turn on if u apply a more negative voltage than the source pin
but dont directly connect the gate to ground, mosfets have max rated vgs, and for those irf stuff i have seen is + -20 for n and p mosfet respectively, connecting directly to ground means vgs=-24 and that means it blows up
and this is very inconvenient because arduino only outputs 5v or 0v
so we will need to use another component, either another transistor or opamp, since using opamp is overcomplicating a simple problem, we will use transistor
we will use an npn bjt, connect emitter to ground, connect arduino output in series with a resistor to base
now make a voltage divider where one side is connected to 24v, middle is connected to gate of p-mosfet and another side is connected to the collector of npn bjt
use equal value for both resistors so when the npn bjt is turned on, the gate voltage becomes about 12v
so now when output is 0v, bjt turns off, gate is pulled up to 24v, vgs=0v, p-mosfet is turned off
and when output is 5v, current goes through bjt and turns it on(base resistor is only there to limit current to prevent arduino and bjt from being damaged, so make sure base resistance is low enough that it can still make bjt go into saturation, turning it completely on), and voltage gets divided at the gate, vgs=-12v, turning it on and perfectly safe
for the last part, we connect the heating wire to the drain of p-mosfet, then the other side of the heating wire to the ground
voila, we made it
when arduino outputs 5v, p-mosfet turns on and wire heats up, when arduino outputs 0v, p-mosfet turns off and wire cool down
now this is where PWM comes in, imagine if you switched ur output on for some time
then switched it off for some time
let's say 60% of the time u switched on and 40% time it is off
that means 60% of the time u r applying 24v
which is same as applying 14.4v constantly
if 50% of the time u switched on, that is equivalent to applying 12v constantly
this is almost like a buck converter but with less extra steps
and analogWrite in arduino does exactly just that, it isnt actually outputting a real analog voltage, it is outputting a 5V PWM, at around 500 or 1000 something Hz
that frequency is fine so u dont have to manually to change the timer register to adjust PWM resolution and frequency
at this frequency, u dont really have to care about gate current or capacitance
remember in ac circuit, Xc is lower when frequency is higher, but Xc is higher when frequency is low, that means current will be lower at low frequency, negligibly low
just assume everything is 0
for heating a wire, u can even use tens of Hz, mybe even 10Hz, 100Hz is also fine
any frequency will produce the same result and same heat, frequency isnt really critical for heating a wire
in conclusion, this is a very simple problem, u just needed 3 more resistors and an npn bjt, base resistor could be something like 2.2k or 680 which will almost certainly ensure saturation, both resistors for voltage divider can be 10k or 2.2k
no calculations at all, dont need to overcomplicate stuff
@u r noob I love your answer. I know that I might be overcomplicating heating a resistive wire. My initial thoughts were that I need a mosfet, that will open power to the wire and then I continued with I need to limit that voltage so I can control the amount of the heat that will be produced. So I jumped to the buck converter and immediately thought about fast switching the mosfet.
My first tries were kinda too hot, because I was almost burning the MOSFET with slowly charging the gate and wrong voltages at the gate. Then I learned about push-pull (totem pole) driver and tried that. I also posted a question about this with a schematic on a stackexchange but instead of some constructive critique or some thoughts I got almost shamed without any explanation.
I was trying to learn everything I can from all kinds of videos so when I learned about push-pull I was eager to use it. Also I want to learn everything about mosfets and how to properly use them.
But I believe that I was overcomplicating that.
Thank you for your answer. That helped me understand a lot. I'll follow it.
@@urnoob5528 I have one question tho, wouldn't the MOSFET burn? I tried your solution in a simulator and there was a 20V drop over the MOSFET.
I'm reminded of the one I saw wherein an "inverter" was made with just a couple transistors and resistors driving an old center tapped power transformer backwards, push-pull, at whatever frequency that mess happened to oscillate at.
I don't know what are you talking about most of the time, but still nice to watch these interesting videos :D
Of course it's not a good circuit, but it's fascinating that it is even possible!
And with said limitations its possible turn the motor in the first place. In my opinion this is valuable information, but its niche market for places that can utilize this stone age esc. Years back i would loved to know about this, for random test contraptions that just need to be thrown together and run in constant speeds. Hell it could simple be used to test brushless motors if those even work. It really does beat expensive and fancy ESC's specially when time and cost are priority over features like "cold start".
The real issue with these videos are that they dont explain the pros and cons of the setup at all with leads to mentioned scammy feeling coming from it.
Thank you for making this video. For some time I have been trying to build a PMA from a car alternator on my channel. Lots of youtubers get fantastic results but I don't. Maybe I know why now.
Great job man!
Thank you! Cheers!
What I've come to learn is the reason why real circuits get so complicated is because the real world is messy and fickle and anything can go wrong. Therefore, the more complex the circuit is the more problems the creator foresaw and accounted for. Every little extra component is there to better ensure the whole thing doesn't break randomly for a weird reason you didn't see coming. It's exactly like bugfixes in computer code. So, I tend to take simple designs like these as more of a proof of the underlying concept than anything practical.
It's funny you mention code - I'm not really a programmer (though I do code), but I am a fairly senior systems engineer. An instant display of naivety is, to me, when I see anybody say "Pfft, I could build that in [x]". You see it so so often in engineering, electronics, IT. Nobody ever seems to stop and think "Maybe it took clever people so long because it's more complex than it looks to get right"
@@hermand Over confidence happens even to the best scientists. Not too long ago, and even now, many scientist still use the word "junk DNA" for non-coding DNA thinking they are garbage. That is like me looking at a computer mother board, and say all these resistors are junk components.
If i see something like this im always thinking - Well there are thousands of really smart people thinking all day about how to create something complex like an ESC and you achieved the same results with 6 simple components... I doubt that 😂
Exactly, every part in any mass manufactured product is there for a reason. Whether or not you know and understand that reason, they didn't waste money putting it there for lulz.
production. Thanks again!
wow! we always have everytNice tutorialng to learn! Great to know you!
I don't know why they're still called that (Brushless DC motor). The ones in stuff like a PC fan, it's the motor and control stuff in one area. But just having like an RC motor, it's not a DC motor. It's a 3 phase permanent magnet motor.
Could it perhaps be due to their lack of brushes?
@@SpeccyMan They don't run on DC, though.
Could it also perhaps be because they are run from a DC power source instead of a synchronous 3-phase AC power source?
@@kimsmoke17 But they're not. They're a motor that requires a controller. How the controller derives its source power doesn't classify the motor it's driving.
Hello guys, iam a 19 years old hobbiest, i tried getting into electronics more than once but failed. I have mulitmeter and some lithuim ion batteries a lot n lots of electric components. I feel like i cant make any circut board and No matter how much i tried understanding each basic component i fail. I bought breadboard but still not able to make any basic circut board.....
Any tips? Iam really passionate about it please inform me
Use an arduino starter kit.
There are these experimental / educational kits which have a very good handbook, explain every step all the parts and the physics, start easy and then get more and more complex. Like the ones of KOSMOS (for example Electronic XN 1000). But there are many more like these.
I recommend watching videos explaining the individual components, like the electronics-101 videos from electroboom. This way, you might understand individual components enough to build circuits.
"The art of electronics" is the book you are looking for
I know that feel. GreatScott! does some really cool shit. His videos inspire me while simultaneously making me feel like I suck at eLeCtRoNiCs. Remember you're only 19 and GreatScott is an electrical engineer.
There are a hundred youtube channels, where some barefoot Indian kid with bugs and chickens walking around everywhere, make some really cool simple projects. You can learn a lot from those videos.
Try watching all different types of electronics videos, keep experimenting, keep learning, and keep having fun with it.
Thank you for this debunk)
Stuff like this has become much more advanced, a basic circuit would be something like a decade counter to switch the outputs in sequence which would give better control, but these days they have precision feedback, current & speed control, waveform control and lots of other features that have been developed over time
If you hear a person with an Indian or a Russian accent telling you what to do with two wires then you run away immediately.
Fun fact, the dislike button is hidden by TH-cam but how can u see it number of dislikes😳😳
fax
There is a chrome extension that allows us to see it
There are Chrome extensions for that ;-)
You can see it if you have vanced on android
You saved me hours of fiddling and building! I was going to try one the simple circuits but now I will just buy one.
This is great info. Been getting into motors of late. I have a large factory three faze motor that I want to add a variable controller to. Now I know not to try something like this, and try to look for a well made pre-built controller. The extra cost to pay, will be worth having something reliable.
How is the first comment on this video 9 days ago??? It was literally uploaded 15 seconds ago. What... The comment is by akhurash
Patreon supporters can watch way earlier ;-)
@@greatscottlab awesome! ;) ;) I might just have to comment 9 days earlier...
Please start working on not ending each word with an "s". I absolutely love your videos, but this one was actually painful to listen to.
When your German is as good as his English........😄
That wont happen he is german
Its not that bads
People talk how they talk. Get over it.
Is it any worse than your ending a sentence with a preposition?
This is how I talk. I try to improve every time. But this is the way it is. End of story.
Great video! 😊❤
Great scott bro big fan of you
aw! 7:29 looks LOL but wow! I love your experiments, inspiring me to do something else to develop it. Thanks soooo much
Thanks for sharing information.
My pleasure
I know I've got a few old motors I can try this with. Thanks Great Scott!
Scott nice video thank you so much... @7:38-> 3 A draw at 15 V at no load is a load for any BLDC 😅 what value of gate resistor did you just curious ? Really well explained i hope more people dont fall for this...
Great video! But I'm curious about that videos like to dislike ratio? How is this possible? I thought TH-cam got rid of that.
Interesting - as always!
Some of us got almost 100% of our electronics components as kids by scrapping electronics we found in the trash. 3 mosfets, 3 diodes, and 3 resistors. that's a really doable project!! motor probably would have come from the trash too so if it burnt up i wouldn't really care so much. I definitely would have done this.
Bro i was waiting for your video for every everyday
Hope you enjoyed it!
Yup bro try to increase the upload speed and decrease the time taken to create an video ..... don't try to make it too perfect.
Waiting
An ESC is simply that an electronic motor speed controller. There are many different kinds on the market that you can also DIY.
But.....there are brushed motor types, brushless motors and everything in between. The key is matching the motor with a proper controller.
My terminator es-04 scooter which was a freebie to me had a bad controller and is no longer made so i had to use a cheap compatible aftermarket controller which after wiring mods works well. Minus the battery gauge but a meter can be added. No biggy:)
Thanks for sharing. 😉👌🏻
This is also the root schematic of a phase-locked-loop (PLL) used in microcontrollers. Each of the three fets feed into one another to produce a distorted sinewave with 120 degree phase shift between each stage. Except, when you throw the inductance of the motor windings onto each leg the phase shift is no longer constant. I had toyed around with a circuit like this years ago to try to use it as a sinewave reference to drive power mosfets in a three-phase half-bridge configuration, but at that point it gets complicated enough that you might as well just build a proper ESC.
Can you please elaborate ?
What's the input/output signals, how does it work to be a phase controlled system in a control loop ?
I have basic understanding of PLL but i can't make sense of your comment
@@weistonaski6924 it is a fixed frequency phase shift oscillator in which the drain pin on one MOSFET phase feeds though a capacitor to the gate on the adjacent fet. Repeat 3x and you have three fets operating in parallel. Drain on each FET is tied to a resistor to source voltage. Like an astable multivibrator which is basically a 2 phase shift oscillator the three FET circuit is a 3 phase shift oscillator. Frequency cannot be adjusted without varying each drain-to-gate capacitance equally otherwise you will have inequal phase shifts due to inequal capacitance time constants.
Yeah, I have done 25 years ago a similar circuitry but with only one transistor for a casete player with the motor driver popped, a custom one ( with control in both directions ), the efficiency was pretty good but needed a capacitor in paralel with the resistor to increase the efficiency and move the switch timing, that capacitor helped at auto starting as well.
Agree, you need to buy a dedicated controller, BUTT, in some cases that one is good enough 🤷♂, there are some country's that work a month to buy a dedicated controller, for them to build a controller with around 1 USD and a good enough performance is a big deal..
Man how you research that beginner as very fit with all of your voice pronunciation and video tutorial so hot....
your prototype builds always have that Frankenstein look lol
You can make full bridge of the same half bridge simple diagram with roughly 18 parts and have a decent motor controller from 0.7v to 55v. I really suggest this method as it's wide range voltage and simplicity.
Saves you from a lot of complications.
This reminds me of the "600W sine wave inverter" which is actually a square wave inverter with an unregulated output producing perhaps a few tens of watts.
Cool. Thanks for the insight
Any time!