scott wrote:
>> Wait a sec - so you're saying there are devices which actually violate 
>> Ohm's law?
> 
> Yes, more exactly, there are devices which do not have constant 
> resistance/impedance.

Are you saying the resistence doesn't determine the current? Or are you 
just saying that the current can cause the resistence to change?

>> Well, you're the one with the engineering degree, but it *still* 
>> doesn't make any sense to me...
> 
> Maybe it would help if you imagined that inside the IC there is a big 
> resistor (eg 1Mohm) connecting the input to one of the supply rails (but 
> you don't know which one).  In order to ensure this resistor cannot 
> affect the input voltage, you need to make sure the input is always 
> connected to the voltage you want through a smaller resistor 

Hmm, OK.

> (electricity likes the lowest resistance path!).

Now, see, I always thought electricity just takes *every* path, with the 
current being determined by Ohm's law.

So, if you have a high-resistence path from A to B, and then you add a 
second, lower-resistence path from A to B, does the current flowing 
through the first path change? Or does it remain the same?

(Clearly the *potential* at A and B will be changed - there's more 
current flowing now...)

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