How does an ALTERNATOR work ? How to TEST each COMPONENT with a multimeter and how to REPAIR it ?
The battery light stays on on my car.
The alternator is in rotation but the battery doesn't charge.
After checking that the issue doesn't come from the car, I test the alternator on the table.
I test it with a drill and observe that it doesn't work.
Before to open the alternator, I explain briefly the role of the
stator and the rotor.
I show you the schematics of the components of the alternator :
The stator, the rotor, the regulator and the diode bridge.
I test the rotor with a multimeter
I test the regulator, this doesn't work.
I test the stator and the diode bridge together and separatly.
I notice that a diode is in shortr circuit on the diode bridge.
I replace the diode bridge by a new and I refit it on the alternator.
Then I refit the alternator in the car.
0:00 Introduction
1:06 Test of the alternator in the car
5:41 Test of the alternator on the table
6:27 Alternator operation
9:02 Presentation of each component of the alternator
9:47 Tests just on the rotor
11:08 Tests just on the regulator
13:44 Tests on the stator and the diode bridge
15:36 Diode bridge removal
16:31 Tests just on the stator
17:52 Inductance measures on the rotor and the stator
19:05 Tests just on the diode bridge
23:02 New diode bridge refitting
25:56 Alternator reassembly and reffiting in the car
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This video has been created for practical, educational, and sharing purposes. It neither constitutes nor replaces a genuine specialized technical manual. EnjoyWheels provides no warranties of any kind and disclaims all liability for the information contained in the videos. Under no circumstances can the author be held accountable by viewers for any adverse effects resulting from the use of the information presented in the content. EnjoyWheels recommends wearing personal safety equipment when carrying out tasks similar to those shown in the videos on this channel. If you are uncertain about the potential dangers of an operation, its consequences, or your own ability to perform it, seek assistance from a professional.
One of the best explained alternator repair videos ever ! It should be used in high schools. Thank you!
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Am paying a lot of money for my engineering degree and am watching this for free 😂😅
Bloody hilarious
Work smart dont work hard
Your better off having that degree though.. and if it's in electric engineering its a good one to have.. 👍🇮🇪🙏
this is the most detailed alternator repair ive watched. 27mins not wasted . you sir earned a subscriber
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I 2nd this comment! Subscribed!
Have never seen a better description and demonstration at the same time. Ever. 👍👍👍
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This is THE best car alternator/battery diagnostic video I’ve seen. 10/10!
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Undoubtedly the Best diagnosis of non charging condition in a Vehicle,and Theoretical Explanation and repair and testing on a Alternator, I've seen well done.
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What can I say? The best best super alternator repair video on KZhead. Thank you so much sir
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God bless you, my Lecturer .That's my field. Also, I didn't know how to test the regulator ... but now I am thank you so much more blessings and may continue securing your life.
Thank you very kindly for your demonstration. Finally, a guy who knows how to explain things in a straight forward and logical way. Bravo!!!
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Perfect work troubleshooting video. Complete step by step explanation and of course the theoretical. I will wait the next and more video from you. Thank you.
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exelent explanation, in detail
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The details he provided was very accurate and in depth showing physical examples of the parts involved and how to check those components (while matching them to a wiring diagram via highlights) and the replacement of one diode.
You are the first to explain that the stator wires are in pairs. Even the shop manual wire diagrams don't show this but now it makes sense. I hate when they dumb down info because I know something is off and then understand that they don't want you to know that much. Just buy another and replace it!
your video format with the real life and then the graphic representation is excellent and helps understanding. thank you.
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New subscriber and this was an excellent description of how an alternator works and how to test one. Thanks for sharing. Artie. 👍
You have taken the time to properly explain how the alternator works . Thanks so much. Being looking for along time.
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One if the not the best video on car alternators and troubleshooting I’ve come across on KZhead. Post-processing must have been time consuming but the end result is fantastic. A good mix between the practical and theory made your video highly engaging to watch. Also learned a few tips about soldering! Well done.
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Thank you for your valuable and very clear explanation of how an alternator works and how to test the various components of an alternator. I was impressed by your repair as well. Thank you again! -Respectfully
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Thank you for a very detailed & well explained video. Switching between the actual part & the wiring diagram made it very easy to understand!
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This has been one of the best education videos of my life, the way you elaborated every step and detailed reasons justifying whys. Please keep up the good work, It really inspire people like me. I am a self learning auto electrician.
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This is the best tutorial I have ever had as an electrician 👏👏👏👏. Good job man.
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Awesome presentation. Outstanding work. Thank you for sharing this.
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Great diagonosis. Most of us would just replace the alternator... as I have done on multiple ocasions on several BMWs, including the water cooled version on my 1999 540 sport wagon. Thanks for the break down of the repair!
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A very clear and elaborate video. I have learnt more about the alternator.
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This is first time to across a lecture like this. Thank you for educating.
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This was fun to watch. Your work flow is very different than pro mechanics, yet still very engaging. Pro mechanics would simply swap the alternator, and a few with extra time on their hands would do a voltage drop test of the B+ wire and a ripple test to look for diode bridge problems. The ripple test could be as simple as switching your multimeter to AC to detect big swings in voltage as the device spins. In this case I like the way you pulled the three components apart and tested each in turn. At one time those three components were sold separately, but today it is hard to find individual parts that are all compatible. In the end it comes down to how much time you want to spend testing and then searching for parts.
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How is a ripple test done
This is the only video I'll ever need to watch about alternators. Im keeping it forever. ❤️
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I enjoyed watching the video, the style of explanation and clarification of the smallest details, with explanatory marks in different colors on the. important points, and I also liked the sense of humor sometimes in the video, wonderful. Thank you for the clarification.
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You're the best! Really appreciate the soldering tips, that's gold for multiple other situations.
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excellent. give this man an award. videos like this deserve a thumbs up
thank you
Very nice video regarding alternator service, its parts,function and testing with the recommended values.good for everyone who like to automotive engineering and industrial engineering as well.
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Very detailed step by step explanation, learned a lot from the video. Thanks!
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We did the Volkswagen alternator is just like that. Good to see somebody else doing the same have a nice day may you be blessed by all the different things in life. You already work the magic lesson share what you learn and be humble
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i just found this vid and love the way you explained it with diagram next to actual component. thank you sir
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Even without a show of face, The explanation is detailed that laymen with a little bit of idea in electronics could understand. Your video is a valuable reference. keep it up and thank you...👋👋👍👍👍
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I've been looking for such an indepth explanation for a long time. Thanks a lot
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Good, perfect, clear, audible narration of fluent and perfect lingua franca! ,👌
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Great job !! First time seeing something so in detail ... repair for an alternator. 👍👍👍👍
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incredible explanation and video. you reason every step in the diagnostics and repair in the easiest way possible to understand.
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Very informative and clean explanation of everything for Alternator :) Interesting that there is a lot of variants how car alternator can be built. Stator windings can be connected as Star Y or Delta Δ, in the case it's just 3 windings output will of them will have 120 degrees phase shift and some ripple. Some alternators use 2 winding groups shifted by 60 degrees between them and 12 diodes rectifier (2x 6 per group). By shifting 2 groups with 60 degrees ripple is much lower which is mean less ripple/noise produced by alternator when charging/providing current for other loads. As for my Mazda CX-9 2022 I found Alternator circuit schematic from MESI Mazda Electronic Service Information, alternator stator have 2 winding groups connected in Delta Δ and shifted by 60 degrees. I think for BMW there should be something similar like electronic service manual/documentation. Thanks for the video and one more subscription from me :)
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Nice fix. Your description of what happened is correct.
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Thankyou for your knowledge I had bought a new alternator replacement as old one stopped charging and fitted it witch worked later came across this video and repaired my old alternator now I have a spare.
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ELEGANT EXPLANATION AND RECONFIGURATION! EXCEPTIONALLY WELL DONE!
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That was a really good explanation for anyone learning electrical repairs on cars. I'm surprised you actually mentioned the diode direction of 'flow', that's very rare outside of an automotive school environment. Well done.
Thanks for your message. Regarding the "flow" word, it's an french to english translation issue
I am a beginner in coming to a knowledge of the truth about electrical theory and electronics. What does electrical diode direction of 'flow' mean and why is it so important? thanks
The flow means the current direction.
My alternator was born in 1997 (I bought my Honda Civic that year) had no problem ever since. Many thanks for this awesome video.
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You are a really really good teacher. Please make one about the starter as well!
I have no starter that doesn't work. Thanks for the message.
A good quick go, no go, first test: 1) Turn the key to on. DO NOT START THE ENGINE! 2) Take a screwdriver, plier or anything steel and touch it to the shaft in the middle of the alternator pully. If it sticks hard like to a strong magnet, the voltage regulator and the field coil wrapped around the shaft are probably good. 3) Go to the other tests shown here. When you go to test the diodes with a multimeter, you MUST know the polarity of the test leads. Depending on the meter brand, the internal battery voltage supplying the probes are not necessarily the same as the probe color codes. Example: Radio Shack and Archer meters made in the 80's and 90's had the red probe outputting a negative voltage as tested with another volt meter. A diode is a "semiconductor". This means when functioning properly, it will pass power in only one direction like a one way valve will only pass a liquid or gas in only one direction. If your continuity or ohm meter has a negative going red probe and you connect it to the anode, (flat bottom end of the diode in the diagram), and the black probe to the cathode, (the pointed end), you will get an indication that the diode is open, (burned out), when it may be perfectly good. When testing diodes in an alternator, they MUST FIRST be disconnected from the stator coils or you may read a shorted condition by inadvertently reading the continuity of a stator coil rather than the diode itself. Whenever checking any semiconductor whether it be in an alternator, amplifier, radio or crystal set, first, set your meter on the X1 or lowest ohms setting then connect the positive going probe to the anode and the negative going probe to the cathode. It is normal to read a few ohms at this point as semiconductors are not a perfect wire. Now, reverse your probes and test again. There should be a 0.0 or infinity reading or, on meters with a needle instead of a digital readout, zero needle movement. If you get any reading at this point, the diode, (bridge in an alternator), needs to be replaced. Another indicator of shorted diode(s) in an alternator is a lower than normal, but present, charging voltage at the battery with the engine running. Normal charging voltages vary by car brand. Ford is between 13.2 and 13.5 volts. General Motors, (GMC, Chevy, Buick. Oldsmobile, Cadillac, Pontiac and Saturn) is around 13.8 and Chrysler, (Chrysler, Dodge and Plymouth) is 14.2. Chrysler police vehicles can be from 14.5 to 14.8 because of extra equipment. Older 12 volt vehicles with generators, at idle, readings can be below 12 volts and still be normal. Increase engine speed to 1,000 RPM and test at battery for 12.8 volt or above reading not to exceed 13.8 volts max. Foreign brands, check with dealer service department for acceptable voltage range. Two ways to test for shorted diode(s).: 1) Set your radio to a dead channel in the AM band. 2) Start the engine. 3) Rev the engine slightly. If you hear a soft hum that changes tone like a siren that changes pitch with engine speed. This can also be noise from the ignition system. If this hum is present, with the engine running, take your meter, set it to "AC" at or near a 12 volt setting and place the probes on the battery terminals. (This will NOT harm the meter.) There should be NO reading at all. If the meter reads any voltage of any kind, one or more diodes are shorted supplying AC voltage to the vehicle's electrical system. This leads to a lower than normal effective charging voltage, could damage the internal filter capacitor in the alternator, irritating noise in some car radios and, if the ECM, (engine control module), has poor filtering or is "well aged", this alternating current, (AC), can confuse it leading to less than optimal engine performance, higher pollutant output and / or lower gas mileage.
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you just put the multimeter on diode test. it should read a voltage drop of around 0,5 to 0,6 on one direction and nothing when you reverse it.....the rectifier assembly should be disconnected from the stator prior to testing...also check shorts between stator and housing and visual inspect for bunrt varnish or burnt smell from stator
Great step by step explanations! Thank you
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Earlier today I watch a video on the electronicsNmore channel and thought it was by far the best video on alternators I've ever seen. The algorithm recommended this video, and now this is by far the best video on alternators I've ever seen.
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You are an excellent teacher, for all automobile Electricians, thank you, I deserve at the age of 67, you are superb.
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Incredible good instruction video, good verbally explained. You are a perfect instructor.!!
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thank you for this very detailed explanation. learning about alternator of how it works...i might be able to fix my own when needed in the future.. very useful to know thanks
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Best alternator video in KZhead. You've got a new subscriber. 🎉
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ONE OF THE BEST EXPLANATION ON ALTERNATOR. AMAZING JOB KEEP IT ON GOING.
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The lesson was very good, explanation and teaching technique was excellent.
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One of the few wonderfully illustrated videos 👍
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This was an enjoyable 27 minute video, and very educational, great job.
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Excellent and detailed explanation. I hope your repair lasts and provides many more 1000's of KM of faithful travel! :D
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Great video with all the details. Consider this video as a class about Alternators.
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Excellent video. Very informative and concise.
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The BEST...BEST...BEST... video I ever watched. Hats off to EnjoyWheels! Sorry I had only one chance on Thump up!!!!!
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what a wonderful video ,very clear with each and every component explained in real and in the diagram. Thank you very much for your time and effort in putting this video.
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Excellent video and very helpful instructions and diagram.
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I am a novice whom you have given certain confidence. Some men are called to teach. You are one of the best. i will not only subscribe, but highly recommend also. Please keep enlightening the lost or misguided hungry for simplicity.
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Video nicely made. Very useful and well explained. The process is very logical. Thanks!
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Good clear complete explanation! Well done very enjoyable to watch!
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Thanks for the video! Excellent explanation!
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Thank You ! Top clear Explain in total in simple digestive manner.
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very well done vidéo ! Explanations are clear and easy to understand. Thanks !
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BEST EXPLAINED ABOUT ALTERNATOR HOW DOES IT WORK AND HOW TO FIX.❤
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Excellent presentation and explanation. Well done
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Amazing presentation! clear voice clear sentence! Good Luck!
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Wonderfully demonstrated. THANKS TO YOU
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Excellent tutorial! This is good for students learning automotive electrical!
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Thank you for making me fully understand video 🎉about alternator.
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I understand everything you said !!!! Thank you very much for the explanation!!!!!!!!!! I feel I'm ready to check my alternator!!!!!
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this video make me feel like i was in class u explain everthing in detail nice work
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I like it! Its informative n helpful. I wish a lot more videos like this produced to serve other components of car.
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This video was amazing. Wow thank you for the knowledge. Now I can check my alternator. 🎉 Thank you sir
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Complete teaching . You got 1000 likes from me ❤❤❤❤❤...
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Very clear unique explanation.i like it.enjoy watching this video. Help full
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Hi, What a well, detailed explanation, and fault tracing video!...I am from South Africa, and my son had a problem, (low charging voltage, on load) on his Ford 1300cc "Tonic" 5 door car. Normal checking battery voltage, with engine off 12v...ok, Battery voltage, engine running 13.8v...ok Now the moment more load is added, (lights switched on etc), charging voltage reduces below 12v etc. After checking similar checks, as per your fault finding video, finding all 6, (NPN and PNP Diodes) ok. No Stator coil wires shorting to "Earth" etc. Also replaced, with new Voltage-regulator...still low charging voltage while load added. Now I went into "Brain-surgery mode" Ha ha!... Reading your followers views, (and noticed that you award each one with a reply...which other video posters don`t always do!), I did`t see anybody mention the other "3 Diode-pack", that the Voltage-regulator uses to "sample" the Stator output AC voltage. Well, coming back to my under charging voltage problem...here was the problem!. 1 of the 3 Diodes, were OPEN CIRCUIT, which then created the low charging output voltage, when on load, to the battery. I replaced the "3 Diode-pack" with a new one and wolla!, Alternator producing full charging voltage on load!. This "3 Diode-Pack" is stuck away, underneath the main 6 output Diode plate. Thought I would just mention, to also check those 3 Diodes etc. Keep up the good Tutoring!. Andy Swanepoel. East London, South Africa.
Thanks for this detailed message. I haven't seen a 3 diodes pack on my alternator.
Well explained! Thank you for sharing sir!
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Very very informative and scientifically explained. Thank you very much.
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Well explained..Now I have a fair idea of fixing my Alternator..Thanks alot mate
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Very nice demonstration and explanation appreciate it 👌👍💐
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The best explanation, You make a wonderful job
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That was very interesting an informative. I would agree with your diagnosis of why the alternator failed.
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Very good demonstration. I enjoyed it thoroughly up to the point of current flow as an electron theory electrons flow against the arrow in diode in the diode symbols, you shown the positive Diode conducts electrons to remove electrons from B+ during the positive alternation, making it more positive the negative diode conducts electrons to add electrons to the battery posts on the negative alteration to make it more negative which charges your battery negative to positive anyway cheers and thank you
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Awesome video and Thank you for taking the time to produce such a detailed step by step analysis of the alternator and each of its components. But that is too much work for a non technical guy like me. As I learned in another video, you can test the diodes by switching the MM to Vac and with the engine running, place the probes on the battery terminals. IF you get a Vac reading, it means there is a problem with the diodes, IF no Vac reading then OK. That was my case, so just getting a whole new Alternator.
Thanks for these informations
Thank you Sir for sharing your knowledge.
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Excellent explanation and use of diagrams. Please make more videos. you got my subscription
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Good job we need more lessons lakini je this in detail 💯🔥🔥
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Amazing work, graphics and explanation!
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brilliant video, very informative and helpful
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Excellent explanation! explains so clear
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Except for the computer generated sounding voice, it is an excellent presentation. Very well organized, clear and concise.
Thanks for the comment. I don't speak english enough well to use my voice, so I use a computer generated voice.
Awesome! Very detailed explanation. Thank you
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Very good to learn therotically and practically 🙏👍
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That was really well done, and very informative , and I got a lot out of it
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Thanks for developing our education 👍👍👍
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