Tinkercad + Arduino Lesson 6: Pull-up and Pull-down Resistors

[ENGrEdge]

Awesome Video.
Currently working on a small project and really did not understand what a pull up or pull down resistor did. This has cleared it for me. Thank you so much!!!

[Johann]

Very good. Only after this video I could understand.

[alexobzor]

Hello! I have spent to find the answer the whole day, your video is the best that i found. I have a question. I already understood that that technology of pull-up and pull-down is used to clarify a condition on digital output, but i don't get the resistor's role i that circuits. Can you asnwer, on 4:12, why should we add a resistor with that ground ? We can add just a ground, and, i guess, electrical noise just will go to that groud, so, what does the resistor here ?

[CamMacDoughnut]

Great video, thank you! I just had one question: @4:36 you said that the lower resistance path was through the Pin, rather than through the resistor to ground... However, earlier you mentioned that a pin configured as an input has the equivalent of a 100 megaohm resistor infront of it... Would this not make the pin the path of higher resistance? I must be missing something. Thanks!

[SammychipOfficial]

best explanation out there my God. Cheers

[glchiu]

wouldn't the current still be flowing through the pull-down resistor to ground, heating it up when the button is on?

[rul]

Ben.... How do you calculate the resistor value????

[AB-nrnv]

How would you make you input pulldown? Is it a pulldown by default?

[katakomn]

I really have a hard time understanding this concept (it been 2 days). then I came to this video. thank god your explanation is great. but still, I have questions:

1. we knew that we need a reference point to measure voltage, but when the pin is reading voltage what does this pin read? the voltage drop in the pin impedance? or the voltage difference between the junction to the Arduino ground? (is the ground you draw is referencing to the Arduino ground? )

2. I watch another video that said that the resistor that you add must have resistance 10x the pin impedance (just a ballpark). if this is the case, I have a problem when we talk about the "open pull-up resistor circuit" because the voltage drop in the pin impedance is small (most of the voltage drop occurs in the pull-up resistor) that make the pin reading can probably enter the LOW range. (i afraid that the pin doesn't measure the impedance voltage drop, so this is related to the 1st question).


other than that this is a very brilliant explanation. thank you so much, hope you can answer my confusion.