Hi Everyone,
I'm working my way through the list of beginner mistakes you've probably all done already. So far I've managed to figure things out, but this one has me stumped. In potentiomiter examples, such as Ada's, why doesn't turning the pot to zero short the output pin to ground? (which I read is one of the things one categorically must NOT do)
Hi Paul,
The analog pin is an input, agreed, but there is also a 5V output on the far side of the pot. When the pot is turned to zero this means there is (almost) zero ohm between it and ground. Is shorting the 5V output ok?
No, there is always whatever the max resistance is, across the two outside connections.
The middle pin wipes along the wire inside, and gives a voltage from 5V to 0V to your i/o pin, but the 5V never shorts to 0 since those outside points are attached to the ends of a (say) 10M resistor.
Now I get it, thanks! I thought the pot was a variable resistor that somehow ACTUALLY varied the resistance by sliding strips of metal, effectively changing the path the electricity went through. Just changing the point at which the potential is measured makes a lot more sense.
Hi Mike, think you could be starting an urban myth there
It might have been more consistent with what us old bods were taught by the likes of Wheatstone etc that "Pot" is actually a contraction of "potentiometer" - which is a form of potential divider.