Good questions, to start you on your way into the analog world.

Let's say that there's a power source with variable voltage. Across
> its terminals is a resistor of 10 Ohms. The power supply can only
> supply a maximum of 1 Amp.
>
> If the voltage is gradually increased, to the point where I =3D V/R > 1
> Amp, what will happen? Will Ohm's "law" not be violated?
>

Without throwing in too many real-world realities, your power supply will
stop at 10 volts, and it will not go any higher.  Even if the knob goes to
11.  And what is happening, is happening inside the power supply.  There ar=
e
going to be internal resistances, and they too will have to behave accordin=
g
to ohm's law.


> In the case of the battery charger example:
>
> A NiMH battery should be trickle charged (assume constant current of a
> few milliamps, rather than a high current pulse). The battery has a
> relatively low internal resistance. How can the current supplied to
> the battery be controlled precisely when the applied voltage is
> relatively constant?
>

One answer is, "it can't".  But what you'd normally do is add a "current
regulator" circuit between your power supply and the battery.  Thing is, no=
w
the "supply" on the battery side of the circuit isn't constant voltage
anymore.

The list should have fun with this one.  Maybe I can trick someone into
describing a "pseudo-constant-current" supply to you.






> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.