Hi,
can anyone direct me to a user friendly tutorial / help on these? How do I choose between the two types and what sizes of ohms etc..
Hi,
can anyone direct me to a user friendly tutorial / help on these? How do I choose between the two types and what sizes of ohms etc..
No need,
I found one here when looking at a previous reply on a different subject:
Here are 3 really good articles:
http://www.seattlerobotics.org/encoder/mar97/basics.html
by far the best overall description I've seen.
http://www.sparkfun.com/tutorials/218
Good description of how to determine exact value for pull-up resistor
Good info on Arduino internal pull-ups
Thanks that's really helpful!
Just out of curiosity, why don't we use diodes instead?
I tried these pull-up / pull-down cicuits on a simulator with 10Meg resistors and they still work. So then I thought a diode could replace the large resistor and
it still worked.
mmm....?
Simulators usually do not handle shorts and opens very well.
A diode is (effectively) a short or open depending on the forward voltage. The resistor allows current to flow regardless of the voltage applied, which is why it "pulls-up/down."
Thanks,
I understand better now.
I'll use 4.7 or 10k resistors on my buttons unless directed otherwise by designs or datasheets.