Computer Inputs: Pull-Up and Pull-Down Circuits

Автокөліктер мен көлік құралдары

There are two types of circuits that are used for computer input signals: Pull-up and pull-down circuits. This video explains how these circuits work so that you can know how to test and diagnose sensor circuits.

Пікірлер: 49

  • @andrewk778
    @andrewk7784 жыл бұрын

    While watching this video, I thought about you, investing equipment and time, all to share your knowledge and experience. NONE of this was available when I was a kid. Thank you for sharing.

  • @Okie-Tom
    @Okie-Tom Жыл бұрын

    You are very good at teaching the very basic understanding of the circuits! Thank you!

  • @J.T672
    @J.T6726 ай бұрын

    Hi Justin, I work for toyota a dealer and these videos are really helpful under standard circuit design . I've also been on various training courses and never seen these explained on anty of my courses .. I think most circuits ,sensors on toyota are pull up design . Really enjoyed the video

  • @sourikishona
    @sourikishona5 ай бұрын

    I don't know in which words I should thank you for this great video...❤❤❤❤

  • @billyyoder8171
    @billyyoder81714 жыл бұрын

    Thank you Justin. Another great job. Have a blessed and safe week to you and your family.

  • @mikemcmanus2815
    @mikemcmanus2815 Жыл бұрын

    Fantastic video! So efficient, so cogent. Well done.

  • @DJ-tn7vj
    @DJ-tn7vj2 жыл бұрын

    Thanks for the video. Appreciate the pull up and down concept that you broke down.

  • @feeneysmechanical6215
    @feeneysmechanical62154 жыл бұрын

    Thank you Justin for everything you do

  • @NewLevelAuto

    @NewLevelAuto

    4 жыл бұрын

    He's been on a roll eh Greg?

  • @hoaxs1939
    @hoaxs19394 жыл бұрын

    Also known as a Voltage/ Potential Divider Circuit. Great video with very good examples.

  • @moparnut6286
    @moparnut62863 жыл бұрын

    Man I love these videos very educational thank you!

  • @alibatebi2161
    @alibatebi21613 жыл бұрын

    on of the best explanation of pull up. pull down circuit. thanks

  • @jgeorges3061
    @jgeorges30614 жыл бұрын

    Thank you Justin for awesome information really appreciate ur time by doing this.cheeers

  • @DylanRabier
    @DylanRabier4 жыл бұрын

    Great video! GM wiring diagrams will show you the symbol for a pull up or pull down resistor.

  • @arthurfricchione8119
    @arthurfricchione81194 жыл бұрын

    Justin you are putting out terrific videos. I just finished setting up some custom probes on my Pico 2205A. Great informative video. This video is also very informative and clearly explained. Thanks for taking the time to share your knowledge. 👍👍👍

  • @JustinMillerAutomotive

    @JustinMillerAutomotive

    4 жыл бұрын

    I'm glad it was helpful. Thanks for the kind words.

  • @mohsinshaikh9513
    @mohsinshaikh95132 жыл бұрын

    Amazing video. Very valuable information

  • @frankyv5999
    @frankyv59994 жыл бұрын

    thank you sir, for your time and knowledge

  • @francisdsa6790
    @francisdsa67903 жыл бұрын

    Exelent professional demonstration thanks 💐🙏⭐⭐⭐⭐⭐

  • @corollagl82
    @corollagl823 жыл бұрын

    I am trying to convert an old kettering system into a kettering - mosfet combination. Thanks for this, you just gave me an idea on how i can switch the p channel mosfet via contact point.

  • @asdautomotive8909
    @asdautomotive89094 жыл бұрын

    Buena explicación de señales de entrada . Pull-up Pull-down

  • @AldiShuli
    @AldiShuli4 жыл бұрын

    Great information, thankyou.

  • @lugmgrm2835
    @lugmgrm28354 жыл бұрын

    Excellent ! Thank you

  • @nickayivor8432
    @nickayivor84322 жыл бұрын

    Very KNOWLEDGEABLE Thanks 👍 Justin Miller From Nick Ayivor from London England UK 🇬🇧

  • @hammerhead6537
    @hammerhead65373 жыл бұрын

    Excellent! Thank you.

  • @JustinMillerAutomotive

    @JustinMillerAutomotive

    3 жыл бұрын

    You are welcome!

  • @udaysubramaniam2530
    @udaysubramaniam25303 жыл бұрын

    Thank you so much!

  • @adelsharaff2362
    @adelsharaff23624 ай бұрын

    thank you so much. I was so lost, not anymore.

  • @shrikantgupta4255
    @shrikantgupta42552 жыл бұрын

    Well Explained

  • @totbob8947
    @totbob89473 ай бұрын

    Good explication

  • @Mewanrahnam575
    @Mewanrahnam5753 жыл бұрын

    Keep going Sir..if you can you please do a tutorial on CAN harware circuit and workings

  • @matthewmiller9855
    @matthewmiller98552 жыл бұрын

    Hello, I really like your videos thus far. Thank you for taking the time to do this for us. I am confused though. I am still very new to this. So I reserve the right to be wrong. I am currently going through scannerdanner's book. What you call a pull-up circuit, he calls a pull-down circuit and vice versa. He says if voltage is from an external source then it is a pull up circuit. Reason being that if the switch is open then the sensing circuit will read 0V when the switch is closed the sensing circuit is "pulled up" to source voltage. Now I am more confused. Maybe it doesn't matter what we call it as long as we understand the circuit. Thank you again.

  • @JustinMillerAutomotive

    @JustinMillerAutomotive

    2 жыл бұрын

    Mathew, I am glad that you are curious! I hope this helps: Without the book in front of me, I am not sure what exactly ScannerDanner is trying to communicate. However, when you use a resistor on an input circuit like this, they are classified as either '"pull-up" or "pull-down" resistor circuits. This video correctly labels them. In a pull-down circuit, the pull-down resistor holds the logic signal to zero volts (0V) when no other active device is connected In a pull-up circuit, the pull-up resistor holds the logic signal to a reference voltage (usually 5V, 8V, or 12V in automotive applications) when no other active device is connected Here are a couple of links about it: www.circuitbasics.com/pull-up-and-pull-down-resistors/ circuitdigest.com/tutorial/pull-up-and-pull-down-resistor

  • @jche4503

    @jche4503

    2 жыл бұрын

    easy way to put it is mechanical or hydraulic switches as fuel injectors are pull up/ power comes from external source grounded at computer. gm fuel pump is pull down power comes from computer and external grounded. what mr miller is referring to is a hall effect sensor or electronic switches like cam shaft or crankshaft sensors. scanner danner goes into detail about these in his premium. mr miller is not explaining what type of switch he is referring too. theres mechanical, hydraulic, and electronic switches

  • @spelunkerd

    @spelunkerd

    Жыл бұрын

    @@jche4503 When we talk about pull up or pull down, we need to remember which resistor we are talking about. The designation in the microelectronics world refers to the actual resistor inside the PCM, put there to give stable voltage even when the switch is open, and to limit current when switch is closed. But in Paul's lecture series I believe he was talking about how the actual sensor, like a fuel pump or temp sensor influences the incoming voltage. I like his idea to identify the two general kinds of circuits, but muddy use of specific terminology can lead to confusion as well. It may sometimes be better to use the terms 'ground side switched', or 'power side switched', for clarity.

  • @jyao5409

    @jyao5409

    Жыл бұрын

    The pull up resistor and pull down resistor are clearly defined. I associate pull up circuit with pull up resistor. And pull down circuit with pull down resistor. This is different than the ground side switched or power side switches circuitry.

  • @Tubecraft1
    @Tubecraft13 жыл бұрын

    thanks for the vid ,I have one question in the door lock example how is it a pull down when the door lock switch applies voltage to the ECU ? have I misunderstood

  • @AutoDiagnosticsPK
    @AutoDiagnosticsPK4 ай бұрын

    Great lecture Justin ❤....one request, please keep your cursor colour darker....yellow colour was making it difficult to follow you

  • @mikeadler434
    @mikeadler434 Жыл бұрын

    👍👍

  • @alibatebi2161
    @alibatebi21613 жыл бұрын

    thanks for very interesting video. so that`s why when cooling temp sensor is unplugged the cooling fan starts working because it default to 5v.so it is pull up design?

  • @JustinMillerAutomotive

    @JustinMillerAutomotive

    3 жыл бұрын

    No, that is not necessarily true. The output circuit is independent of the input circuit. That may be a fail-safe programmed into the computer so that the engine does not overheat if the sensor circuit has a failure.

  • @paulalmquist5683
    @paulalmquist56836 ай бұрын

    your yellow circle pointer is very hard so see against the light yellow background. Make it darker like blue or black for better contrast, better visibility.

  • @hichamsaid9472
    @hichamsaid94723 жыл бұрын

    Dear sir I have a question about the three-wire sensors (we suppose it works with 5 v), when we unplug the connector from the sensor, we get 5 v or zero volt on the signal wire I am so confused.

  • @JustinMillerAutomotive

    @JustinMillerAutomotive

    3 жыл бұрын

    It all comes down to understanding how voltage drops in a circuit, including knowing where voltage drops (or doesn't drop) when the circuit is open. The input circuit is a voltage divider circuit. When you unplug the connector from the sensor, the circuit is open and voltage will not drop across the internal resistor in the computer. Because of that, you will get either 0 volts or 5 volts depending on whether it is a pull-down or pull-up circuit.

  • @hichamsaid9472

    @hichamsaid9472

    3 жыл бұрын

    @@JustinMillerAutomotive thank you so much

  • @sheerwillsurvival2064
    @sheerwillsurvival20646 ай бұрын

    Every video I watch seems to say something different. High side switched or low side switch. And scanner danner says pull down when you unplug goes to 5volts 🤦🏼‍♂️

  • @JustinMillerAutomotive

    @JustinMillerAutomotive

    4 ай бұрын

    I have not personally heard Scanner Danner say this, but others have told me that he is teaching it backwards. Don't hold that against him. He's still a very good teacher. Everyone makes mistakes and learns as they go. It doesn't take very much research online to confirm that a pull-up resistor will default to 5 volts when unplugged and a pull-down resistor will default to zero volts when unplugged. I have been teaching for over 20 years and have certainly taught some wrong principles along the way! I hope I am learning and getting smarter as I go!

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