Extreme noob electronic question

[Marc Nostromo [M-.-n]]

>> I undestand the capacitors are used to stabilize the ac changes in the
>> DC supply. Does that mean I can't use polarised caps ?
>
>
> in this case, they're not there for that reason.
> in the old school, you used to have to rectify AC, then use capacitors to
> smooth it into DC, which is what I think you're referring to.
>
> Now the 7805 will take a 9V DC signal and make it 5V DC, so there's no need
> to smooth the signal. Check the data sheet for your 7805 as they can often
> run from 6V to 18V for input, but not all. But note, it takes 9V *DC* and
> regulates it to 5V DC. i.e. if you have 9V AC going in, this just won't work
> for you :)

I meant the variations in the DC supply, just like you said. I'm still
mixing my terms up.

> Bigger capacitors work at lower frequencies, so the bigger the capacitor the
> more low frequency noise it will get rid of.
> Bigger capacitors are bigger physically and to keep the size down, they're
> often made "polarised" this helps keeps the physical size small. you can get
> non polar 100uF capacitors, but they massive and expensive.

So I could pretty much put any capacitors at both ends (I understand
it filters more or less low frequencies depending on the values) ? The
ones in the datasheet are not that big and I've seen a lot of schema
with very different values.

While I'm digging the subject, why is there a 100n and a 220u
condenser next to each other in  Olivier's 'Mutable' regulators.

See for example top corner of

http://mutable-instruments.net/static/schematics/Shruthi-Analog-LP2Delay-v02.pdf

One for the dc stabilisation and one for load 'balancing' ? I've read
something about it but it still fails to click.

/M


--
http://marc-nostromo.com