Electronics 201: Pull-Up and Pull-Down Resistors

Ғылым және технология

In this Electronics 201 lecture, we talk about the useful tool that is the pull-up and pull-down resistor. We also go over the concept that is the tri-state buffer.
I'm looking for suggestions for future videos, so if you have any topics, just put them in the comments below.
As usual you can check out my blog at
8bitprojects.blogspot.com/

Пікірлер: 227

  • @leonardomelia92
    @leonardomelia923 жыл бұрын

    I've watched other's, yours explain everything, doesn't take many things for granted, it's complete and clear as well

  • @bgable7707
    @bgable77074 жыл бұрын

    Finally, a "complete" explanation which made sense, thank you

  • @jeremyo1457
    @jeremyo14579 жыл бұрын

    Im really happy how you talked about in detail the floating state in the beginning, a lot of other videos dont talk about that and why anyone would want a pull up or down resistor. Thank you for helping us!

  • @sd4dfg2
    @sd4dfg212 жыл бұрын

    Thanks! I had looked up the definition of pull up and pull down resistors several times without it making sense - now I see it was because I wasn't thinking about impedance.

  • @daktariTJ
    @daktariTJ6 жыл бұрын

    One of rare youtube videos I let commercials roll (muted). hHD, your work is appreciated. thanks

  • @roflcopterszz
    @roflcopterszz8 жыл бұрын

    Thanks for the video friend, I really learned a lot about "philosophies in creating circuits" and electricity in general because of the ways you displayed this information! THANK YOU! it's rare to find such clear and concise conveyance of information on this subject

  • @Tubepkp
    @Tubepkp12 жыл бұрын

    Thanks a million! I am kind of playing with basic electronics for three years and thanks to you now I really know what is going on inside. Simply GREAT!

  • @ganeshsrinivasan842
    @ganeshsrinivasan8427 жыл бұрын

    key take aways 1. floating is bad 2. current is lazy , takes the path of least resistance 3. Impedance is your friend. thanks for the clear explanation

  • @ericlindau2039
    @ericlindau20396 ай бұрын

    Thanks for talking about impedence. Finally makes sence to me. I've tried to wrap my head around this for a while, never thinking of that the mcu has a resistance.

  • @abolilakhe
    @abolilakhe7 жыл бұрын

    This makes so much more sense now...Thanks for the tutorial!

  • @alih2975
    @alih297510 жыл бұрын

    Well done, very useful Value R of Pull-Up just wanted to point out that in the Pull-Up case, the value of the Pull-Up resistor has to limit the current flowing to the input pin and ground. it is preferred to be 10 times less than the impedance of the pin otherwise, a loading effect will be present as a result of the voltage divider, hence it is better to have the Pull up resistance Value R as 10 times less the impedance of input pin.

  • @drhane

    @drhane

    6 жыл бұрын

    Good point, Ali H. Input impedance is desired to be high while output impedance is desired to be low.

  • @BLAKskyyy
    @BLAKskyyy8 жыл бұрын

    Thanks for this, the explanation and analogies were excellent! It really helped a lot!

  • @cannnonfoddder
    @cannnonfoddder11 жыл бұрын

    Very clear. Champion tutorial mate. 10/10 would watch again.

  • @wickedchin
    @wickedchin11 жыл бұрын

    Thanks heaps for the unique way of explaining the concept pull-up and pull-down resistors - it's the easiest to understand so far!

  • @sheetanshkaushik
    @sheetanshkaushik11 жыл бұрын

    Finally, one video to answer all!! This is a GOOOOOOD VIDEO!!!

  • @ohmedarick1
    @ohmedarick16 жыл бұрын

    Thank you Great explanation. I thought I was the only one not able to understand the concept by the comments below

  • @Gruggo
    @Gruggo6 жыл бұрын

    Dude, amazing video, I have no idea about electronic circuits, but this helped me understands some of these Arduino demo projects i'm building. Thanks heaps mate.

  • @mikeburch2998
    @mikeburch29983 жыл бұрын

    That was a great video! I learned a lot quickly. Greetings from Arizona.

  • @chain3519
    @chain35199 жыл бұрын

    Thank you for this video, it thoroughly explained that logic is not on and off, but High and low. I had then misconception that it was High and off, but this video helped me realize that off can not be a logic state as there is an absence of info.

  • @nicholaselias8542
    @nicholaselias85428 жыл бұрын

    Awesome video!!!! Thnx for the explanation were learning about this in automotive engine performance/diagnostics

  • @cthutu
    @cthutu5 жыл бұрын

    Fantastic video - allowed me to explain the concepts better to my electronics club!

  • @BenDavis78
    @BenDavis7811 жыл бұрын

    Great tutorial, answered a lot of questions for me. Thanks!

  • @jimadams2473
    @jimadams247310 жыл бұрын

    Dude, very good instructional videos on electronics basics. I have watched three so far and plan to view more. Man, you should do many more of these on more electronics topics. How about one on H-Bridge motor controllers. Keep up the great work.

  • @pumbo_nv
    @pumbo_nv5 жыл бұрын

    Now this is a more or less decent explanation, though not perfect. I had watched a few other videos on pull-up/down resistors and this is the first video I liked. Thanks. Now FINALLY it makes sense to me why and how it works.

  • @Pwe56
    @Pwe564 жыл бұрын

    Thanks for the video! Quick and clear explanation.

  • @yassinal-nuaimee1204
    @yassinal-nuaimee12042 жыл бұрын

    Best video on the subject out there

  • @metroiddude123
    @metroiddude12311 жыл бұрын

    Great video, man. Very informative, thanks a lot!

  • @LukePuplett
    @LukePuplett10 жыл бұрын

    I thought Wikipedia's entry on this subject was concise and explained the concept really clearly, hope it helps someone: "A pull-up resistor weakly "pulls" the voltage of the wire it is connected to towards its voltage source level when the other components on the line are inactive. When all other connections on the line are inactive, they are high-impedance and act like they are disconnected. Since the other components act as though they are disconnected, the circuit acts as though it is disconnected, and the pull-up resistor brings the wire up to the high logic level. When another component on the line goes active, it will override the high logic level set by the pull-up resistor. The pull-up resistor ensures that the wire is at a defined logic level even if no active devices are connected to it. A pull-down resistor works in the same way but is connected to ground. It holds the logic signal near zero volts when no other active device is connected."

  • @pumbo_nv

    @pumbo_nv

    5 жыл бұрын

    As a beginner, I can tell that it's not explained well.

  • @davetriplett8109

    @davetriplett8109

    5 жыл бұрын

    I need to read it a couple times, but that makes sense to me😎

  • @judo-rob5197
    @judo-rob51973 жыл бұрын

    Always was a source of confusion for me. Thanks for making it clear now.

  • @Kahain
    @Kahain9 жыл бұрын

    Thank you so much for this video, i watched so many videos but they are all confusing except for yours. I just got started with the official arduino starter kit and i completed the project number 02 and also completed project 03 but i was still stuck at project 02 as to why there was a 10k resistor after the switch. I knew it was a pull down but a co worker today just confused the heck out of me and it turns out you confirmed i was right from the beginning. I'm so happy to learn my logic is healthy lol, there is nothing i hate more than thinking logically and be wrong and have no clue why. I can finally move on because of you. You're the best!!! And... I subscirbed to your channel, there seem to be a few good videos to watch laters, i just dont know how many but cant wait to find out.

  • @PatrickHoodDaniel
    @PatrickHoodDaniel11 жыл бұрын

    Excellent tutorial. Best explanation I could find.

  • @JasonPoindexterus
    @JasonPoindexterus12 жыл бұрын

    Great lecture. Made it crystal clear.

  • @ags-engineering5544
    @ags-engineering5544 Жыл бұрын

    Pull-up and pull-down resistors well explained, thank you !

  • @JamesSleeman
    @JamesSleeman12 жыл бұрын

    Excellent description, this is perhaps the least head-hurty description of why a pullup/dn resistor works, and more importantly, why a given value is chosen.

  • @DannyPost
    @DannyPost9 жыл бұрын

    Thanks for this! I was having some trouble grasping what each type did but this seemed to help.

  • @craigwilmot9045
    @craigwilmot90453 жыл бұрын

    Excellent tutorial. This subject was a always a bit fuzzy to me but not now!

  • @fumil4489
    @fumil44895 жыл бұрын

    Good tutorial!! Easy to understand. Great job!Thanks!

  • @larsinsgd
    @larsinsgd8 жыл бұрын

    Brilliant! You made me understand this. Many thanks

  • @mikekorkowski4794
    @mikekorkowski47949 жыл бұрын

    Very good description!

  • @JohnDoe-fv5cu
    @JohnDoe-fv5cu7 жыл бұрын

    Great! Very good explanation of the idea

  • @digihz_data
    @digihz_data5 жыл бұрын

    Excellent explained.

  • @syahrialrasyid2539
    @syahrialrasyid2539 Жыл бұрын

    thanks for the explanation. It's very clear

  • @WhoWantsToKnow81
    @WhoWantsToKnow8110 жыл бұрын

    Excellent tutorial, thanks! Floating = bad? That's not why my swimming instructor said...

  • @___xyz___

    @___xyz___

    6 жыл бұрын

    What did he say?

  • @ytrew9717

    @ytrew9717

    5 жыл бұрын

    dad's joke

  • @lumpusmaximus8100
    @lumpusmaximus81006 жыл бұрын

    Even if it's kinda confusing cause of the used words, it's still a very good video and better than the other ones available for pull-up and pull-down resistors.

  • @ketkisonawane5048
    @ketkisonawane50485 жыл бұрын

    Amazing explanation!! Thankyou so much!!!

  • @cameronfrost5924
    @cameronfrost59249 жыл бұрын

    Thanks, cleared things up a little for me.

  • @GetUpAndJump0
    @GetUpAndJump012 жыл бұрын

    Nice lecture! Keep up the good work :)

  • @josh_m
    @josh_m10 жыл бұрын

    This was helpful, thanks!

  • @VViproz
    @VViproz11 жыл бұрын

    Nice tutorial, you're very clear, thank you !

  • @allanonmage
    @allanonmage11 жыл бұрын

    Woa I know pull up and down resistors. Thanks for the great explanation!

  • @Andefir
    @Andefir3 жыл бұрын

    Thank you, very useful video

  • @kopaczp
    @kopaczp5 жыл бұрын

    Very educational video! I clearly understood pull up finally. You should do lectures on Polish school. Cheers!

  • @heejune
    @heejune11 жыл бұрын

    this helped me a lot, thank you!

  • @gihangamage6615
    @gihangamage66152 жыл бұрын

    best explanation even in 2021

  • @phani9676725
    @phani967672512 жыл бұрын

    really your lecture helped me a lot in understanding that concept...thanks brother...

  • @navneeths459
    @navneeths4596 жыл бұрын

    Thank you buddy....really saved me a lot of time.....thank you....

  • @ganeshsrinivasan842
    @ganeshsrinivasan8427 жыл бұрын

    'current is lazy' :) good one.. easy to remember the concept.thanks

  • @DupczacyBawol
    @DupczacyBawol7 жыл бұрын

    201 = You Are The Best.

  • @tedthisius4778
    @tedthisius47785 жыл бұрын

    I think of a pull up or pull down resistor like a mechanical spring. Since the symbol for a resistor looks somewhat like a spring it is easy to remember. With a pull up resistor it is like a spring which tries to keep the voltage level at the level of the pull up source. Using a switch to ground "stretches" the spring down to Ground. Once the switch is released the "spring" returns the voltage to the higher voltage of the pull up source. With a pulldown resistor, the spring is trying to hold the voltage level down but can be stretched upward when the button is pushed.

  • @ali101819
    @ali1018194 жыл бұрын

    7:45 why would any current gets pulled straight to ground when the resistance of the pull down resistor is larger than the mcu, isn't it suppose to go to the mcu instead because it has lower resistance ?

  • @PriyankaDanda
    @PriyankaDanda6 жыл бұрын

    Thank you! It was very clear :)

  • @coolguy336
    @coolguy3366 жыл бұрын

    Hi there, I think you meant to say that pull up resistor should be 1/10th or 10% of pin. In the case of pull up with V+ at 5V, 10kohm resistor vs 1kohm pin means that by simple voltage division, you actually have 0.45V at microcontroller pin which defeats the whole purpose.

  • @TorstenLohr
    @TorstenLohr9 жыл бұрын

    Hey m8. Thanks for my daily dose of education. :-)

  • @cman32826
    @cman328268 жыл бұрын

    Aspiring computer/mechanical engineer here - this was VERY helpful!

  • @aryesegal1988

    @aryesegal1988

    8 жыл бұрын

    likewise brah. g/l for the both of us! ;]

  • @programmingelectronics
    @programmingelectronics10 жыл бұрын

    Fantastic explanation - Great video. Thank you!

  • @smithclk
    @smithclk10 жыл бұрын

    Thanks a lot! Very helpful...

  • @EnergeticWaves
    @EnergeticWaves4 жыл бұрын

    if i have a 10k resistor and say 40 inputs on a mega and do the pull down thing, will all that power going into the resistors be too much and will it heat up the resistor too?

  • @ashishraghav8241
    @ashishraghav82416 жыл бұрын

    very good teaching ...

  • @amandafalke7670
    @amandafalke767010 жыл бұрын

    Well done!

  • @kristopherhensel7555

    @kristopherhensel7555

    10 жыл бұрын

    hot!!

  • @djantony8501
    @djantony85019 жыл бұрын

    good explanation mate. thanks

  • @humanHardDrive
    @humanHardDrive11 жыл бұрын

    What microcontroller are you using?

  • @pavanbobba
    @pavanbobba4 жыл бұрын

    Thank you for the nice tutorial...

  • @MrACG66
    @MrACG668 жыл бұрын

    In case of pull down resistor. When the switch is open why the current would not choose the MC path because it has less resistor? Thank you

  • @Ziplock9000

    @Ziplock9000

    8 жыл бұрын

    +MrACG66 Yes, he explains that concept in reverse for the pull-up.

  • @Tim-vd-wal
    @Tim-vd-wal10 жыл бұрын

    On 7:38, lets say that µc has an impendance of 10Ω, which means that the resistor should have 100Ω, correct? Why is the floating current choosing ground over the microcontroller when ground has a resistance of 100Ω and the microcontroller has a resistance of 10Ω?

  • @haydenoverseas

    @haydenoverseas

    10 жыл бұрын

    He applied the one tenth value to the wrong resistor.... Your question is justified. From another website: The general rule is to use a pull-up resistor that is an order of magnitude (1/10th) LESS than the input impedance of the input pin (10k-100k). An input pin on a microcontroller has an impedance that can vary from 100k-1MΩ

  • @smartaIec
    @smartaIec6 жыл бұрын

    Something I don't understand... When you close the switch in a pull up resistor circuit like the one in the video, the 5v connects directly to the ground, with only the resistor in-between. Would this not fry the resistor?

  • @HeuristicObfuscation
    @HeuristicObfuscation10 жыл бұрын

    Nice tutorial.....does this apply to pull down resistor value for mosfets? you mentioned R= 10* impedence input.

  • @marshalcraft
    @marshalcraft9 жыл бұрын

    so if i didnt know if a chip encorperates the pull up resistor for i2c and i put the resistor in, it wouldnt effect the i2c at all. so basically always put in a resistor and 5v supply for i2c?

  • @seanocansey2956
    @seanocansey29568 жыл бұрын

    conceptually, would it be better to have a pull up resistor as this saves power in a microcontroller? instead of constantly letting it run to GND with a pull down.

  • @jeshwanth100
    @jeshwanth10011 жыл бұрын

    Excellent!!

  • @alewarten
    @alewarten4 жыл бұрын

    But in the case of pull'down resistor noise signal would also go to MCU (since it has lower impedance) instead of the ground?

  • @Kazmuth666
    @Kazmuth66612 жыл бұрын

    love your video bro...

  • @mihirpatil515
    @mihirpatil5156 жыл бұрын

    very nice explanation

  • @firoz9751
    @firoz97515 жыл бұрын

    Nice lecture

  • @ut4321
    @ut432111 жыл бұрын

    Great stuff, man! Thanks. I need to translate this from your switch example to interfacing a microcontroller (output) to an LDO voltage regulator chip that has a handy extra pin to control on/off. I'll think on it a bit...

  • @WeTourLessReps
    @WeTourLessReps10 жыл бұрын

    Stupid question but WHY exactly is the resistance "pulling up" your input voltage ? (as stated in my courses)

  • @boogele
    @boogele4 жыл бұрын

    Pull up is active low - when button is "active" pin is low. Pull down is active high - when button is "active" pin is high.

  • @TelemanNers
    @TelemanNers11 жыл бұрын

    When you say the pull up circuit is built in to most uC's, does that include the Arduino? If so, does that eliminate the need for this and allow you to just wire 5v to button to pin?

  • @logarithm0
    @logarithm05 жыл бұрын

    I FINALLY understood this

  • @knssoftware6018
    @knssoftware60188 жыл бұрын

    Thanks for a great tutorial! There is something that i still do not understand, and i see others with the same query, however the responses seem to be addressing different issues: In a PULL DOWN scenario, when the switch is OPEN, why wouldn't the 'stray voltage' still choose to go to the path of least resistance to the micro controller [with the lower built in resistor], than go straight to ground [with the higher pull down resistor], which was the whole point - to stop the stray voltage entering the pin...

  • @jackbud427

    @jackbud427

    3 жыл бұрын

    i have no idea either. Did you ever figure this out?

  • @GC-dz1sn
    @GC-dz1sn6 жыл бұрын

    This never made sense to me until now cheers

  • @johnbrumfield6212
    @johnbrumfield6212 Жыл бұрын

    Great vid. How do you measure the input impedance?

  • @inglese2996
    @inglese29962 жыл бұрын

    On the pull down, with the switch open, why is there any current flow at all from the ground?

  • @maheshbabu4276
    @maheshbabu42767 жыл бұрын

    I heard Pull-up concept is also used to increase the voltage level of the sensor when sensor gives comparably lower values. How does this pull up resistor used in that application ?

  • @3oriigingaming
    @3oriigingaming6 жыл бұрын

    So if my pull-down resistor had a resistance value that's 10x the impedance, no current is gonna flow to ground? In other words, the current isn't gonna divide up at the junction?

  • @MinhVu-fo6hd
    @MinhVu-fo6hd8 жыл бұрын

    Can anyone explain to me again why the Impedance in the micro-controller is our friend? How does it work when we have a lot of current and when we have a weak signal? Do we still benefit from keeping one resistor (impedance) or do we have to change the resistor (impedance) to get good results in those 2 scenarios? thank you!

  • @aliutesleem4046
    @aliutesleem40464 жыл бұрын

    But when I drew that same circuit on proteus using a led instead for a micro controller, I still have to flip the switch before the led comes on and you said for pull up when it’s open it’s on

  • @petersage5157
    @petersage51577 жыл бұрын

    Aren't gates with internal pull up resistors typically "active low", as in connecting them to ground opens the gate?

  • @kevinjulestv6410
    @kevinjulestv64108 жыл бұрын

    what is the difference between pull up signal or pull down signal control? which is controlling?

  • @johnnguyen8827
    @johnnguyen882710 жыл бұрын

    I have just one question about the pull down resistor circuit: I understand how the current flows when the switch is open (the ground sucks all the current away from the micro controller leaving it with a low state). But when the switch is closed, why does the current flow into the micro controller when the impedance (resistance?) is higher than a 10K pull down resistor? Wouldn't the current flow to the path of lowest resistance towards the ground? Thanks

  • @Sembazuru
    @Sembazuru11 жыл бұрын

    Excellent video. I would just like to point out that while floating pins on _inputs_ are generally considered bad, a floating pin on an _output_ is either doesn't matter, or is required like with multiple outputs on a buss configuration. The floating output would (obviously) be a separate video, but it should be stressed on this video that the "bad" label is applicable here only because this video is dealing with inputs.

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