Voltage divider | Circuit analysis | Electrical engineering | Khan Academy

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  • Опубликовано: 26 ноя 2024

Комментарии • 94

  • @insufferable_wretch
    @insufferable_wretch 2 года назад +13

    Here's another approach to the voltage divider problem.
    Step 1.
    Find the current.
    I = V/Rseries
    = 6/2+6
    = 6/8 = 0.75 Amps
    Step 2.
    Use Ohm's Law(V = IR) to find the voltage drop or voltage difference for each resistor.
    V1 is the voltage drop for R1 and V2 is the voltage drop for R2.
    V1 = IR1
    (2a) = (0.75A)(2ohms)
    V1 = 1.5V
    V2 = IR2
    (2b) = (0.75Amps)(6ohms)
    V2 = 4.5V
    Step 3.
    Kirchhoffs Voltage Law states that the sum of the voltage differences in a given circuit must be equal to zero.
    Use Kirchhoffs Law determine if the circuit is valid.
    We have a 6V battery connected to two resistors in parallel.
    The first resistor has a resistance of 2 ohms and the second has a resistance of 6 ohms.
    When the current from the battery travels across R1, the voltage drop is 1.5V (6V - 1.5V = 4.5V). Reference 2a in step 2 for math.
    When the current runs across R2, the voltage drop is 4.5V(4.5 - 4.5 = 0). Reference 2b in step 2 for math.
    Since we started with 6V and the circuit "used" all of it, we have determined that this circuit does follow Kirchhoff's Law.

  • @Peter_1986
    @Peter_1986 5 лет назад +60

    "Voltage division" would be a pretty badass name for a heavy metal group, to be honest.

    • @Newbport849
      @Newbport849 5 лет назад +7

      No, No it wouldn't.

    • @Peter_1986
      @Peter_1986 5 лет назад +7

      @@Newbport849
      Eh whatever, you already have names like "AC/DC", which is actually an abbreviation for "alternating current/direct current".
      Also, with "division" I don't just mean "inverse multiplication", I also mean "team" or "group".

    • @Newbport849
      @Newbport849 5 лет назад +4

      @@Peter_1986 Anything engineering has no place in heavy metal.

    • @JCarrollTV
      @JCarrollTV 5 лет назад +25

      Newbport you must be fun at parties.

    • @5gallonsofwater495
      @5gallonsofwater495 5 месяцев назад +2

      @@JCarrollTV bold of you to assume he gets invited to any

  • @triplea9994
    @triplea9994 8 лет назад +22

    I wish I had this when I was studying in uni. Very useful and informative. Keep up the good work.

  • @muhammad_hamza_chemE_dev
    @muhammad_hamza_chemE_dev 4 года назад +8

    I am grateful to you that you are teaching the students with great passion and making the courses easy and interesting.

  • @5ravee5
    @5ravee5 Месяц назад

    This is perfect! now I finally now how to calculate and get voltage divider correctly! thanks forever.

  • @CrispymexicanDUCK
    @CrispymexicanDUCK 8 лет назад +97

    Hmmm. This would have been handy last semester... Oh well.

    • @blackswan4301
      @blackswan4301 7 лет назад +1

      Un-Professional Duck lol same thoughts here...ducky

    • @NiggaSlayer666
      @NiggaSlayer666 6 лет назад +1

      that what she said

  • @cinthiaduarte8443
    @cinthiaduarte8443 7 лет назад +18

    i really have to say that I'm grateful for this video i have been trying to figure it out for the past six hours

    • @h.k3260
      @h.k3260 4 года назад +2

      Got ya degree yet? Asking for a friend

    • @cinthiaduarte8443
      @cinthiaduarte8443 4 года назад +5

      @@h.k3260 lol i cant believe i clicked on this and reliving the moment. But yes, yes I did. and def not in physics.

    • @h.k3260
      @h.k3260 4 года назад +2

      Dats doooooooopee

    • @bilalshah4112
      @bilalshah4112 5 месяцев назад

      sooooo.....did the video help? :D

  • @alexanderc5312
    @alexanderc5312 5 лет назад +41

    does Khan do all these lectures? does he literally know everything?

    • @0726-o9b
      @0726-o9b 4 года назад +15

      I don't think this one was done by khan, the voice is different. but yeah khan can teach a lot of subjects very well. physics, chemistry and especially math. I don't know about other areas like computer science but if I'm not mistaken he read computer science at Stanford so im sure he makes great videos of cs too. However most of the videos are high school or junior college level only I suppose, I don't think you'll find anything higher than that. They aren't experts in everything :)

    • @ok8570
      @ok8570 4 года назад +6

      Video is done by Willy MacAllister,
      Written in description.

  • @curtpiazza1688
    @curtpiazza1688 Год назад +1

    Great! I like when you show the derivations! 🎉

  • @miguelandrade7630
    @miguelandrade7630 6 лет назад +10

    Thanks for the explanation !Trying to understand electronics *-*

  • @blockeduser5769
    @blockeduser5769 6 лет назад

    When V out is used to power the gate for example on a small transistor that barely sinks 10 milliamps its not very relative to speak of. But when V Out is sinking current into a substantial load of for example Amps. Now you have the current passing thru R2 and whatever is in parallel to R2 (load on V out) which is completely relevant to the current passing thru R1. So if my memory serves me right you Thevenize R2 and the Load attached to V Out and use the parallel value of the two as the actual number in the current equation. Usually when I want to calculate how many volts are going to drop across a voltage divider I just use the percentage ratio and multiply the voltage by that number. But I remember using this method and its accepted and easy to understand. 8)

  • @doge5603
    @doge5603 3 года назад

    Couldn't understand the formula that I got, thank you whoever made this.

  • @surajmahendraramraj3870
    @surajmahendraramraj3870 3 года назад +3

    I really do appreciate this video .
    And thanks for telling the case where our assumed current wasn't negligible.

  • @xila8861
    @xila8861 6 лет назад +2

    Thankyou khan

  • @LesleyPorter-hf7qr
    @LesleyPorter-hf7qr 10 месяцев назад

    Thanks for the video and explanation

  • @bigworldmemes
    @bigworldmemes 8 лет назад +10

    can you also make a video on current divider
    i0=it(r1/r0+r1)

  • @rajangupta5039
    @rajangupta5039 5 лет назад

    Thanks for such an easy explanation of this topic

  • @kashif2309
    @kashif2309 5 лет назад

    Thank you so much!

  • @sidekick3rida
    @sidekick3rida 7 лет назад +7

    It would've been helpful to see an explanation of the math

  • @mariaabinasj9767
    @mariaabinasj9767 6 лет назад

    The video is really useful and understanding

  • @milesemanuelpaavola7994
    @milesemanuelpaavola7994 7 лет назад +1

    Thank you for sharing. Helps immensely.

  • @uNpOpuLArOpInION69
    @uNpOpuLArOpInION69 3 года назад

    if you understand this you also know what a pontentiometer is

  • @aselim20.
    @aselim20. Год назад +1

    I wrote it.

  • @tamukabasera2044
    @tamukabasera2044 5 лет назад

    thank you

  • @shwetasureshnaikar
    @shwetasureshnaikar 2 года назад

    best and most simple explanations always ◉⁠‿⁠◉

  • @ultikintil
    @ultikintil 8 лет назад +1

    THANKS A LOT

  • @aravindm16
    @aravindm16 8 лет назад +2

    Hey ,shouldnt the arrow direction be up to down for the 6kOhm resistor? because the current is flowing up to down through the resistor right?

  • @texasspinesurgeon
    @texasspinesurgeon 5 лет назад

    excellent

  • @robbrenton9438
    @robbrenton9438 6 лет назад

    Cool story, bro !

  • @rj-nj3uk
    @rj-nj3uk 6 лет назад +1

    Thank you. I need videos on Engineering Electronics circuits too. Stuffs including frequency response. Transistor biasing. Small and large signals. IC 555 timer. Oscillators etc.

  • @MohammadAlshahrani
    @MohammadAlshahrani 6 лет назад +1

    What about the accuracy? stability as long as R is function of T, temperature?

  • @0726-o9b
    @0726-o9b 4 года назад +2

    you sometimes referred to v_in and v_out as "v one" and "v zero" and you wrote 6 6/8 as in it's a mixed fraction instead of 6 * 6/8, made me less confident that you're focused on what you're saying but overall good video and I understood the concept, thank you ^^

  • @vishalkondal8090
    @vishalkondal8090 7 лет назад

    Thanks sir

  • @moazelsawaf2000
    @moazelsawaf2000 5 лет назад

    Thanks a lot sir

  • @jennas7003
    @jennas7003 8 лет назад +22

    I think you keep using "v1" when you mean to be saying "vi" it is confusing

    • @mohshahud
      @mohshahud 6 лет назад +5

      i think hesays v in

  • @orderofchaos8680
    @orderofchaos8680 5 лет назад +1

    what is the meaning of v_out if the output voltage changes significantly when a load is connected to it??

  • @gaithkaleel8381
    @gaithkaleel8381 8 лет назад

    awesome man

  • @power-sp3km
    @power-sp3km 8 лет назад +9

    that Tom Hanks voice XD
    thank you for the video

  • @fairytail6804
    @fairytail6804 8 лет назад +7

    So Vout will always have little to no current? What's the use of it?

    • @rennierrodil6119
      @rennierrodil6119 7 лет назад +1

      Fairy Tail nope it is because the vi in the video is also at little to no current

    • @riflebusters1
      @riflebusters1 6 лет назад +2

      HEYYYYYY FAIIIRYYYYYYY TAILLLLLLLL!!!!

  • @anandh1967
    @anandh1967 2 месяца назад

    There is no current passing through horizon 0 but voltage is Vo, how?

  • @arunk8663
    @arunk8663 3 года назад

    If a resistor is connected across the battery for a long time, then won't it drain off the battery/cell. Can you please let me know ? (3.7V cell 4.7K X 2 connected across as shown in this video)

  • @stanbolvin
    @stanbolvin 5 лет назад

    Isn’t current in the wrong direction?

  • @thanaa6401
    @thanaa6401 2 месяца назад

    Why is gonna v0 be affected only by R2? it ran through both R1 and R2

  • @123123mike
    @123123mike 10 месяцев назад

    Not sure of the math @3:58 isolating Vo, etc

  • @beamer.beamoflight
    @beamer.beamoflight 6 лет назад

    Do you have any examples for bridge circuits?

  • @MrWTFish
    @MrWTFish 7 лет назад

    Is this same for parallel circuits? i saw my teacher do this a different way wtf his way was inverted the other way, both add up on top and at the bottom the divider is the voltage in R that youre trying to find

  • @DevinDTV
    @DevinDTV 8 лет назад +5

    Why's V out only affected by one resistor? What is v out in the first place, and what's the point? idgi

    • @Raidom
      @Raidom 5 лет назад +7

      I know it's been 2 years, but I'm answering just in case someone will also need an explanation regarding what you asked, so here it is :
      1)Why is V(out) only affected by one resistor ? Because it's only applied across one resistor. If it was affected by both resistors, then you'd get the exact same voltage as you applied V(in).
      2)V(out) in this case is a predictable fraction of V(in) as the output V(out). Roughly speaking, you take an applied voltage V(in) and make it smaller as an output V(out) using a divider.

    • @kenziehans6598
      @kenziehans6598 5 лет назад

      Raidom im about to have my final exam in like 1 hour and all i dont get is voltage divider like what the hell is vout i still dont understand

  • @rahulkothapalli202
    @rahulkothapalli202 7 лет назад

    what software you use to teach??

  • @Sethclement96
    @Sethclement96 6 лет назад

    6:12 if i wanna know the voltage for R2 i would just go 6V/(R1+R2) X R2
    Its easier in my head that way. First i divide the voltage over the total resistance so now its spread out evenly, and i have like a base value i guess and then i multiply it by the resistor value i want t find the voltage for and i get the right answer. Can someone tell me if there is anything wrong with doing it this way?

  • @fatpenguin1500
    @fatpenguin1500 5 лет назад

    You wrong 6v and didn’t use that to find the current to use in the equation. You just plugged it in as if it was a current value.

  • @abdesselamtabsart660
    @abdesselamtabsart660 6 лет назад

    Hi ? Please if I use variable résistance 8k can I find 4,5 volt and thank you v much

  • @aimanshafiq2374
    @aimanshafiq2374 6 лет назад

    Okey we know that in order to get the Vout we need to pick R2 as our reference and it would be i = Vo / R2. Because R2 at the below.
    But what about the sensor that can change the value of resistance and its installed at the R1.. how do we know the value of Vo for that?
    Can u please help me out?

  • @lookatmenowbh
    @lookatmenowbh 7 лет назад +1

    so what if there was a current and it wasn't just 0,how do we solve it ??

    • @thobi6639
      @thobi6639 6 лет назад

      Then the resistors would be parallel and have the same voltage

  • @mutd789hgmlkrt7
    @mutd789hgmlkrt7 4 года назад +1

    who else is here cuz of his igcse exams

  • @ahmadroshan1903
    @ahmadroshan1903 6 лет назад

    Why does Vo depend upon R2 and not R1

    • @reubensammichenjoyer
      @reubensammichenjoyer 6 лет назад

      Because Vo, as you can see at around 6:00 , is measured across R2, therefore you need to take that resistance in account.

  • @avargas6669
    @avargas6669 6 лет назад

    Explain how you got 4.5 please.

    • @SoumilSahu
      @SoumilSahu 6 лет назад

      6*6/8 = 36/8 = 4.5. Simple elementary math

  • @HamedAdefuwa
    @HamedAdefuwa 5 лет назад

    These lessons have been very beneficial for me but this one needs redoing please. There's little to no explanation of anything. It's all a bit random. The math at 4:00 made no sense to me.

    • @Technovore88
      @Technovore88 5 лет назад

      Ok, so do you understand the 4 prior equations and what they solve for before that ?

    • @HamedAdefuwa
      @HamedAdefuwa 5 лет назад

      @@Technovore88 yeah perhaps i have a gap in my math skills somewhere but how vout/r2 = vin/(r1+r2) then goes to vout = vin * r2/(r1+r2) makes no sense to me
      I get hes multiplying both sides by r2 but his answer is confusing and he didn't explain it at all

    • @Technovore88
      @Technovore88 5 лет назад

      @@HamedAdefuwa Gotcha, I do agree it would have helped if he had stated the given current in the circuit so it could be proof checked with ohm's law. Just be clear you have grasp of the mathematics up to his actual answer of 4.5 volts for the most part?

  • @hekk_tech5975
    @hekk_tech5975 5 лет назад

    something more advanced?

  • @tucoremirezful
    @tucoremirezful 6 лет назад

    Current through R1 and R2 = I, not i !!!!!!!

    • @dandingerat
      @dandingerat 5 лет назад

      doesnt' matter, theyre used interchangebly

  • @ameamanaviation9412
    @ameamanaviation9412 6 лет назад +1

    This is wrong... Current flows from negative to positive

    • @Abish_
      @Abish_ 5 лет назад +1

      Electrons flows from -ve to +ve...
      But conventional current flows from positive to negative

  • @mahikagupta3971
    @mahikagupta3971 5 лет назад +1

    umm so i see that this video is for college students pursuing electrical engineering... but but but i am a student of grade 8 nd studying it..so unfair!!!!

  • @madushanprathap9901
    @madushanprathap9901 4 года назад

    Thank You

  • @jacquelinelam1914
    @jacquelinelam1914 6 лет назад

    thank you so much