Extreme noob electronic question

[Tony Hardie-Bick]

On 18/01/13 15:17, Marc Nostromo [M-.-n] wrote:
> While I'm digging the subject, why is there a 100n and a 220u
> condenser next to each other in  Olivier's 'Mutable' regulators.

this is down to the imperfections of real world capacitors. generally,
the bigger they are, the more inductance they have, which prevents them
from smoothing especially fast transients (like the transistor switching
Paul mentioned), so a common solution is to put a high value and a low
value right next to each other. In a microprocessor circuit, you might
know that all the switching is the instantaneous stuff, like zero to 5V
in 25nS etc, which only a small capacitor can deal with, and in fact,
the microcontroller usually has some fairly tight specifications for
placing such a capacitor nearby, and, if you're really pushing it,
specifically what make and model of capacitor you can use (most extreme
examples being switched mode inverters).

fun fun fun....

actually, electrolytic capacitors are an awesome example of applied 
nanotech,
although nobody ever calls it that. manufacture involves creating an 
insulator
a few atoms thick, by passing a current through the structure. As the 
insulator
grows, it leaves gaps which attract more of the current, so these get 
filled in
while the existing insulator fails to grow any thicker. amazing, but i 
digress...

Tony (HB)