EEVblog 1397 - DC Voltage & Current Source Theory

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  • Опубліковано 30 лис 2024

КОМЕНТАРІ • 242

  • @EEVblog
    @EEVblog  3 роки тому +59

    Sorry, re-upload for extra clarification. Saves hundreds of comments over the next few years.

    • @Ujwal5555
      @Ujwal5555 3 роки тому +1

      what was the problem with the original video ? Sorry, I couldn't watch the original one.

    • @power-max
      @power-max 3 роки тому +1

      @@Ujwal5555 Here is the link to the original one: ua-cam.com/video/Mf0NmCVI23Y/v-deo.html but he made it private so oh well.
      I did watch the first half of the original one and I think he is mostly clarifying his erroneous claim that the solar panel is a constant voltage source. Most other people model it as a constant current source with a 'compliance voltage' although in the end it doesn't really matter.

    • @chitlitlah
      @chitlitlah 3 роки тому

      I managed to see the original before it was taken down, so I wonder what's different so I don't have to rewatch it.

    • @EEVblog
      @EEVblog  3 роки тому +10

      @@Ujwal5555 Just some extra clarification on solar cells and their CV/CC characteristic curve.

    • @Ujwal5555
      @Ujwal5555 3 роки тому +2

      @@EEVblog Thanks for the clarification ! Dave you should make a video about explaining how micro inverter works and they sync with the grid. Maybe tear one down as well.

  • @treyistheway101
    @treyistheway101 3 роки тому +158

    I would have paid double for my electrical engineering degree to have this guy explain it instead. Great to refresh and relearn things!

    • @lucvanhove9639
      @lucvanhove9639 3 роки тому +5

      Sure, here in Belgium, the minister of education skip electronics and replace it for electromechanica. In the high tech industry, they need electronics, so the new employees receice a one week powerpoint course from some idiote (copy paste from google) . They all receive a degree, but 🤦‍♂️🤦‍♂️🤦‍♂️🤦‍♂️🤦‍♂️

    • @p_mouse8676
      @p_mouse8676 3 роки тому +1

      I actually would have finished my degree. The morons back in the day were so much in their own theoretical bubble, absolutely no one understood anything from those courses, let alone the practicality of it.
      I figured it out myself on my own way. It's actually actually extremely powerful when you dive in equivalent circuits for mechanical analogies.

    • @TeacherBrunoOneil
      @TeacherBrunoOneil 3 роки тому +4

      Me too. My professors were really bad at teaching. They always wanted to approach circuit analysis mathematically first. That sucks. I guess I studied that in circuit analysis I.

    • @TeacherBrunoOneil
      @TeacherBrunoOneil 3 роки тому

      @Sean M more important than what you will teach is how you will teach it. The focus on teaching isn't the subject but how much of it the students will pick. That's how I see the situation. Today I am an engineer but at the beginning, if you have a teacher who has no good didatics to teach, chances are the most students will take longer to learn. My teachers' method were too conservative they focused on calculus nearly all the time. That's important but you choose when you will use it, especially with beginners.

    • @ki4dbk
      @ki4dbk 3 роки тому +2

      @@lucvanhove9639 yeah. It sucks how the authoritarian classroom environment often takes the fire, joy and magic out of learning science and technology.

  • @discontinuity7526
    @discontinuity7526 3 роки тому +53

    Hey Dave, just graduated electrical engineering with distinction and got employed, very glad I had the support of you and your content for the ride, looking at this thumbnail made me think back to the recent past where I struggled with all of this, and I'd always turn to your channel for help, thank you for doing such great work Dave

    • @EEVblog
      @EEVblog  3 роки тому +7

      Glad to hear!

    • @roseelectronics4582
      @roseelectronics4582 3 роки тому +2

      @@EEVblog You deleted my best comment, Dave.

    • @EEVblog
      @EEVblog  3 роки тому +9

      @@roseelectronics4582 If that was on the previous video, that's because I had to re-upload and all comments are lost. It's the way youtube works. I don't just delete comments.

    • @TeacherBrunoOneil
      @TeacherBrunoOneil 3 роки тому

      We all struggled. Lol and that's for sure.

  • @a1nelson
    @a1nelson 3 роки тому +78

    Really pleased to see a new fundamentals video. They're great. Looking forward to more. Thanks

  • @AllElectronicsChannel
    @AllElectronicsChannel 3 роки тому +31

    A class by Davenin 😁

  • @ArcFlashWarning
    @ArcFlashWarning 3 роки тому +41

    Please do more of these. We could all use the reinforcements just as footballs Vince Lombardi reinforced what a football was to his Super Bowl teams

  • @soniclab-cnc
    @soniclab-cnc 3 роки тому +6

    It doesn’t matter how many times you go over this stuff. You can always learn more and gather a better understanding of the fundamentals. I would have loved to have Dave as my instructor...

    • @DarkMatterX1
      @DarkMatterX1 3 роки тому

      Facts. My electrical theory prof was a working engineer at Motorola. Smart guy, knew his stuff, but wasn't the best at getting information across.

  • @mikemike7001
    @mikemike7001 3 роки тому +7

    A nice blend of theory and practice, where Dave goes the extra mile (as usual!) and takes us from the whiteboard to the bench, explained in the way I think an engineer thinks. Looking forward to more.

  • @captiveimage
    @captiveimage 3 роки тому +2

    Superb. Theory with a simple, well delivered explanation followed up with practical demonstration that reiterates the theory. Love these fundamentals vids.

  • @omniyambot9876
    @omniyambot9876 Рік тому +1

    I need to comment so Dave knows that these videos are useful especially for students like me. Electronics engineering for the win!

  • @topquark22
    @topquark22 3 роки тому

    Dear Dave, You are so enthusiastic. It is infectious. I could not imagine how you could make a channel about bits of silicon so exciting. And I love the little troll with green hair sitting on the ledge of your white board/

  • @twobob
    @twobob 3 роки тому

    Solid, and thorough. Articulate reiteration and passionate precis. Appreciated.

  • @adonis0red
    @adonis0red Місяць тому

    The best Tutorials on youtube, Thanks

  • @jgurtz
    @jgurtz 3 роки тому +3

    Funny thing about that guy is his name is a real tongue twister when trying to say it in English, but actually rolls right off like buttah when saying it in French. Thanks for the explainer Dave!

  • @McTroyd
    @McTroyd 3 роки тому +1

    Wow... an explanation of current and voltage sources without high-level algebra or obfuscated math constants! I love it. 👍

  • @KevinNguyen1
    @KevinNguyen1 3 роки тому +14

    If you thought you have seen this video before, then you did see it before! This is a reupload of the video with some extra clarification as EEVblog has said.

    • @Guineh76
      @Guineh76 3 роки тому

      Yeah. He pulled the original video as I was watching it and I was really enjoying it, too. Lol

    • @karpiewscy
      @karpiewscy 3 роки тому +1

      Thanks a lot for the clarification. I watched it around 1 am tonight (Europe) to fall asleep, and when I woke up and could not find it even in the YT history I thought I dreamed it all up!
      Just wasn't sure how I could make up the Norton's equivalent. I remembered only the Thevenin theorem from my high school :D

  • @jeffm2787
    @jeffm2787 3 роки тому +1

    Always good to see a fundamentals video. 👍

  • @laboratoriodeprojetos1351
    @laboratoriodeprojetos1351 3 роки тому +4

    Ótimo vídeo sobre alguns fundamentos da eletricidade. Abraço Dave.

  • @johnmanzang7272
    @johnmanzang7272 3 роки тому

    Another well explained and great fundamentals video! Thank you very much!

  • @hedleyfurio
    @hedleyfurio 3 роки тому

    Super to see you back at the whiteboard 👍👍

  • @TomLeg
    @TomLeg 3 роки тому

    Excellent intro to Thevenin & Norton

  • @advanceringnewholder
    @advanceringnewholder 3 роки тому +1

    Great teacher goes a long way

  • @stewartthompson72
    @stewartthompson72 3 роки тому +1

    Love these kind of videos Dave. It has been a lot of years since I thought about those theorems. Keep it up!

  • @DrJALAGHARI
    @DrJALAGHARI 3 роки тому

    Thanks for sharing this valuable information.

  • @amirmograbi
    @amirmograbi 3 роки тому

    I've never seen it explained so well, thank you !

  • @Sal3600
    @Sal3600 3 роки тому +4

    Your videos are used at Victoria University by our lecturers.

  • @axelBr1
    @axelBr1 3 роки тому +1

    Traditionally chemical plants use 4 to 20mA values to communicate measured values from the transmitter to the controllers and then from the controllers to the valves etc. Many years ago I somehow managed to build a variable current source to generate a current signal to simulate a transmitter for use with a PLC I had on loan. I spent ages worrying about what voltage it should use. I used a 9V battery, and no smoke. The box actually got used but the company project team to check out indicator loops at site in the end. But to this day, I still don't know what the loop voltage should be.

  • @Francesco-bu1hh
    @Francesco-bu1hh 3 роки тому

    Thank you Dave. Please do more of these!

  • @travisporco
    @travisporco 3 роки тому

    Really great to see this kind of content.

  • @ondrejgratz4088
    @ondrejgratz4088 3 роки тому

    Perfect, thanks. This made me remember my 1st grade at electrical high school which was looong time ago.

  • @abdurrahmanyaman4373
    @abdurrahmanyaman4373 3 роки тому

    I just searched "current source eevblog" and this video came up. Same day that video uploaded :)

  • @jeffb.6470
    @jeffb.6470 2 роки тому

    Thank you Dave Jones.

  • @fullmoon6661
    @fullmoon6661 3 роки тому +2

    Reminds me of when I did an internship in a government agency.
    I was redirected to their electronic & instrumentation division, my mentor presumably is an 'expert' on this field and given a task for me to build what I know now as bench PSU with CV CC capability. He explained hell lot, it overwhelmed my still innocent uni student brain. It didn't make a lot of sense what he was explaining, about the circuit has to be sourcing constant in voltage AND in current........... I got back to him how does that make sense if the Ohms Law math doesn't even add up? And what happens if you unplug the port where does the current go? He just said that the Ohms Law doesn't apply in this application. I never felt so betrayed that I was unable to complete this task, mostly my fault because I was so dumb.

  • @stevenspmd
    @stevenspmd 3 роки тому

    Yes more fundamentals please. I've been learning on my own using YT videos for the last year and just signed up for the edx self study electronics course. For me, I do find it is quite easy to gloss over terms like super position and linearity but taking the time to get familiar / explicit about the basics leaves me feeling much less confused when it comes to understanding theorems, etc.

  • @SnowRaptor
    @SnowRaptor 3 роки тому

    14:08 Wow, Dave! With that simple graph you did a much better job at explaining the maximum power point in a solar cell than all "solar and battery" youtubers I see trying to do that! (At least to me, a physicist that can easily visualize the power as the area of that rectangle ;) )

  • @leogray1091
    @leogray1091 3 роки тому

    Although I have masted the idea about this topic. I still love to see this kind of content being produce. Great job Dave! BTW, I love your enthusiasm when you make these videos, much more fun than lectures.

  • @PomTheFrog
    @PomTheFrog 3 роки тому +1

    Thévenin : To be pronounced in two syllables : “Tey”+ “Vnin” to make it simple 👍

  • @remontlive
    @remontlive 3 роки тому +1

    Ou yes, Dave! Fundamentals Thursday again!

  • @jaguarpaw1638
    @jaguarpaw1638 3 роки тому

    love this tutorial so happy please do more. Although I submitted a piece of coursework about Thevenin's theorem but was marked down for using the term "good enough for Australia"

  • @joeyjustin6895
    @joeyjustin6895 3 роки тому

    THANKS. DAVE. HOW'D You Know I NEEDED All This. You are EXELLENT. Thanks again For Another Educational Video. YOUR Great ! See ya next time.

  • @samuelbauer7646
    @samuelbauer7646 2 роки тому

    I really appreciate your videos. Keep up the great work 👍

  • @andymouse
    @andymouse 3 роки тому

    I love the basics stuff, very well explained, personally can't get enough, I should have paid more attention at skhool !....cheers.

  • @NicolasDeFilippoOK
    @NicolasDeFilippoOK 3 роки тому

    Aunque no conozca bien el idioma te deseo lo mejor del mundo amigo 👏👏👏👏👏😎 muy buenas explicaciones

  • @bensonwr
    @bensonwr 3 роки тому +2

    Remembering stuff I learned 30 years ago. I thought had long gone. Thank you!

  • @markusherrmann9681
    @markusherrmann9681 3 роки тому

    Hy Dave, please do more of these fundamental videos. Your explanations are so good. Thanks a lot.

  • @BoB4jjjjs
    @BoB4jjjjs 3 роки тому +1

    You should do a complete series of these videos.

  • @AlmightyDemon
    @AlmightyDemon 3 роки тому

    Dave is teaching me electronics since freshman year in college

  • @protocolfree
    @protocolfree 3 роки тому

    now we're back on track. lovely!

  • @lasersbee
    @lasersbee 3 роки тому

    Interesting Dave... Well explained as usual. Been a while since your last Theory tutorial...

  • @JWH3
    @JWH3 3 роки тому

    This video was enjoyable just to hear you saying Thevenin that many times.

  • @excavatoree
    @excavatoree 3 роки тому +10

    Don't feel bad about "Theremin." Bob Pease once said "carbon compensation" resistor instead of "carbon composition."

  • @mikemike7001
    @mikemike7001 3 роки тому +1

    The prequel to EEVBlog #819 on Kirchoff's laws, more than 519 videos and 5 years later!

    • @roseelectronics4582
      @roseelectronics4582 3 роки тому

      Colleges teach Kirchoff's laws before thevenens.

    • @EEVblog
      @EEVblog  3 роки тому +2

      Better late than never!

  • @ovalwingnut
    @ovalwingnut 3 роки тому

    Rated #1 by Re-Volt magazine. Ben approved this video.

  • @Saimoun82
    @Saimoun82 3 роки тому

    YYYEEEEESSS - I LOVE the videos with the white board!!

  • @georglinde3910
    @georglinde3910 3 роки тому

    That is funny, I teach customers about hydraulics and I find it extremly important to understand the difference of a 'constant pressure source' (e.g. accumulator) and a 'constant flow source' (e.g. gear pump) and there is no ideal source in real world... this is the perfect analogy to this stuff here. :-D

  • @wonderboy7768
    @wonderboy7768 3 роки тому +1

    New eevblog, time to crank the low-pass filter.

  • @mscir
    @mscir 3 роки тому

    Great class, thank you.

  • @74LS_NE555
    @74LS_NE555 3 роки тому

    I really like these videos please keep them coming

  • @babeandbii6051
    @babeandbii6051 3 роки тому

    That whiteboard is better than the other one you tested the other day

  • @jenniferwhitewolf3784
    @jenniferwhitewolf3784 3 роки тому +1

    Practical quiz for younger generation... You are designing a new reproduce amplifier for a tape recorder. The head that reads the signal on the tape is basically a coil of many turns wrapped around laminated stack of magnetic metal. The stack has a gap in it, oriented to face the passing tape. The magnetic signal on the tape induces a magnetic reaction in the laminations, that in turn, generates electron flow in the coil of wire surrounding it. Here is the question.. is it better to treat the inductive signal source as a Thevenin voltage source, or a Norton current source? ...and why?
    HINT: Both methods have been used... but which is better?

    • @unlost117
      @unlost117 3 роки тому

      Dang, you are going back in time. But it probably represents current day card readers.

    • @MM-lv8ib
      @MM-lv8ib 3 роки тому

      Norton because the current is constant across the circuit?

  • @StefanSchlott
    @StefanSchlott 3 роки тому

    Loved it, thank you!

  • @silverywingsagain
    @silverywingsagain 3 роки тому

    So we use both of these models because they represent the ideals. For the the ideal voltage source would need to supply infinite current, and the ideal current source would need to supply infinite voltage.

  • @ebarbie5016
    @ebarbie5016 3 роки тому +2

    The two circuits are not exactly equivalent. The Norton circuit is lossy and the Thevenin is lossless...

  • @LambdaHalbe
    @LambdaHalbe 3 роки тому

    Thumbs up for the nice Casio Basic calculator from the mid 80ies. Unfortunately I can't read the typ label from the video but it seems to be a FX730P, which I have in my collection.

  • @duxforddude
    @duxforddude 3 роки тому

    This was brilliant thank you!

  • @vdiallonort
    @vdiallonort 2 роки тому

    Love your videos, i learn so much with it. Just a head up ,in French we do not pronounce the h,so pronunciation of thévenin is pretty much "Tévenain". Cheers

  • @SpeedDeamon95
    @SpeedDeamon95 3 роки тому

    Man, your probably one of the few people I would pay for a Circuits 1&2, video course! 😁

  • @CraigHollabaugh
    @CraigHollabaugh 3 роки тому +8

    Here's a question my networks professor posed 40 years ago, let's see who knows the answer. "You have 2 sealed enclosures with 2 binding posts. One has an ideal Thevenin source, the other an ideal Norton source. How can you tell which is which without opening an enclosure?" Anyone?

    • @tgfcujhb7583
      @tgfcujhb7583 3 роки тому +8

      Short circuit them , first one to let out the magic smoke WINS.🤣👍

    • @JohnBurgessMusic
      @JohnBurgessMusic 3 роки тому +3

      I'm guessing that the Norton source would dissipate power without anything being attached to the terminals due to the shunt resistor. BTW I always thought Rs in the Norton equivalent circuit meant shunt, not source resistor.

    • @nisserot
      @nisserot 3 роки тому +1

      There would be no discernible difference.

    • @oliverthane2868
      @oliverthane2868 3 роки тому

      The constant current source would be arching between the terminals in the air

    • @EEVblog
      @EEVblog  3 роки тому +1

      @@tgfcujhb7583 Just measure the voltage, one of them will blow up your meter with infinite voltage :-D

  • @MonochromeWench
    @MonochromeWench 3 роки тому

    Keep increasing the voltage of an open circuit to produce a current you're going to eventually cause arcing and you get your current flow

  • @e74av
    @e74av 3 роки тому

    OMG you threw me back 15 years back.

  • @clems6989
    @clems6989 2 роки тому

    Very good video and great udea.

  • @MattyEngland
    @MattyEngland 3 роки тому

    Cheers Joe 👍

  • @Reapzorian
    @Reapzorian 3 роки тому

    Thanks Dave

  • @MiniLuv-1984
    @MiniLuv-1984 3 роки тому

    Dave, Dave, Dave...how many times do you have to tell me? On a serious note, can you do an in-depth on solar panels - how to work out the curve given Isc and Voc - which is what we get on the label. Maybe a series - LiFePO4 cells, PWM chargers etc. - perhaps a practical series covering practical equivalent circuits for each source/sink. I think this will possibly be interesting to many people who are now toying with solar panels, batteries etc.?

    • @MiniLuv-1984
      @MiniLuv-1984 3 роки тому

      Oh, yes, please use DaveCad(C) liberally.

  • @oliverthane2868
    @oliverthane2868 3 роки тому

    This stuff really starts to become important the minute you get a smu to play with

  • @ajinkyamahajan5736
    @ajinkyamahajan5736 3 роки тому +1

    New addon to my knowledge base.
    But yet I didn't understand the current sources shown in circuit diagrams of various datasheets and what is their physical circuit. The only description given is a current sources with symbol of two intersecting circles (like a Venn Diagram).
    Someone please explain

  • @girishss5118
    @girishss5118 3 роки тому

    Sir thanks, It was enlightening 💡

  • @sdrc92126
    @sdrc92126 3 роки тому +3

    People use to have to pay hundreds and even thousands of dollars for this level of instuction.

    • @jope4009
      @jope4009 3 роки тому +1

      Or buy a used textbook for $5.

  • @ultraderek
    @ultraderek 3 роки тому

    In the circuits analysis final we had to find the value of a resistor in a circuit (I know crazy, right?). The resistance needed up being negative.

    • @deang5622
      @deang5622 Рік тому

      A gyrator circuit, a Negative Impedance Circuit using an operational amplifier will provide a negative resistance.

  • @francismannion7075
    @francismannion7075 3 роки тому

    Ah, that was great. Thank you.

  • @daspolemon
    @daspolemon 3 роки тому

    Could you make an in-depth fundamentals video about inductors? How they behave in different circuits, how to calculate them, etc. Would be great!

  • @hrnekbezucha
    @hrnekbezucha 3 роки тому

    Woohoo! Thanks, Dave!

  • @dominicgoodwin1147
    @dominicgoodwin1147 3 роки тому

    Thanks for another great video! Just one little piece of total pedantry I can't help adding though... "If you hear anyone talk about Thevenin equivalent circuits..." then they don't know that you pronounce it like "Tevenin", not "Thevenin".

  • @Robolizard-ph8du
    @Robolizard-ph8du 3 роки тому +1

    This guy explains things better than most teachers

  • @alicangul2603
    @alicangul2603 3 роки тому

    Hi Dave, can you do AC fundamentals like this? Starting with magnetics, machinery, AC impedance, phasors, AC power and power flow, symmetrical components, power system dynamics and so on? UA-cam EE audience is unaware of a vast unexplored [*] field, I would love it if you open that world to us. I remember in an Amp Hour podcast you talked about something related to this.
    * By 'unexplored' I mean there is not as much quality content on UA-cam as with electronics.

  • @martinda7446
    @martinda7446 3 роки тому +1

    Tevenin I think is close to correct and easy with a silent 'H'.

  • @69Atho
    @69Atho 3 роки тому

    Super conductors are ideal components.

  • @dustinsmous5413
    @dustinsmous5413 3 роки тому

    Also in the PLC world, voltage source versus voltage sink...

  • @БарсФиатонов
    @БарсФиатонов 3 роки тому

    I wonder what was first on white board: black marker vertical line or blue marker word "current"?

  • @GlennHamblin
    @GlennHamblin 3 роки тому

    Nice video, thanks.

  • @ChristieNel
    @ChristieNel 3 роки тому

    A perfect current source is called a Tesla coil. It just makes lightning and treats the air as a conductor.

  • @TrickyNekro
    @TrickyNekro 3 роки тому +1

    I mean, it´s easier to calculate the Thevenin Equivalent and convert it to Norton. I guess you could do the opposite if you design with BJT but haven´t really seen it yet.

  • @ziadfawzi
    @ziadfawzi 3 роки тому

    Thank you.

  • @jimomertz
    @jimomertz 3 роки тому

    I guess the power line coming into my house is a voltage source. It didn’t like being shorted at all. 💥

  • @dennybarton9572
    @dennybarton9572 3 роки тому

    I got an old Budgit 1 ton hoist , it's so old Budgit don't even have the right diagrams any more , not sure what motor it has , most of the writing on the tag is gone but it has 5 wires , 4 bigger wires , A 1 , A 2 , S 1 , L 2 , and , F 1 , being a black , smaller wire , not sure how to wire it up to a drum switch, nor even sure what voltage, any suggestions ?

  • @TomLeg
    @TomLeg 3 роки тому

    Excellent

  • @tuttocrafting
    @tuttocrafting 3 роки тому

    Is he the real Dave?
    Too many tutorials in those days!
    BTW, I love thoose videos,you're helping a lot of people!

  • @RaviKumar-xx7gi
    @RaviKumar-xx7gi Рік тому

    Hi I have made the circuit of LM317 on bread board. I am generating a constant current of 100mA. The input to the regulator is 3.3vdc. 100mA constant current is fed to a resistor of 100 ohms. I should measure a voltage across resistor of =10mA x 100= 1000mV=> 1V, but the voltage across the resistor I am measuring is 3.3vdc. why so? I want to use the constant current source to find the unknown resistor using current and voltage How can I do this?

  • @chitlitlah
    @chitlitlah 3 роки тому +6

    To all you who don't speak English as a native language: sometimes even natives have trouble with the th sound.

    • @MrAlFuture
      @MrAlFuture 3 роки тому

      Yep! There's also another accepted pronunciation of Thevenin with a hard "t" as in tetris. That's how we learned it at uni.

    • @Damien.D
      @Damien.D 3 роки тому +3

      Too bad the Th in this case is simply pronounced T. The H is completely silent.
      "Te-ven-un"

    • @chitlitlah
      @chitlitlah 3 роки тому

      @@MrAlFuture Yeah, in French the th would be just like a t. Still, the word could be an English word and would be somewhat tough to pronounce.

    • @nickburak7518
      @nickburak7518 3 роки тому

      Yup...Or the 'V' sound. He he

  • @datnguyenp
    @datnguyenp 3 роки тому

    I have seen some power supply schematic with the output load being represented as a current source and not a typical resistor. Does this mean the output current is constant and not variable depending on the load resistance? You can find some of them on TI’s WEBENCH Power Designer tool