Extreme noob electronic question

[Jon Stutters]

That diagram's not hugely informative but so far as I can tell the LM7805 is fed with DC (from a rectifier if you're drawing power from the mains).  The caps are serving to smooth out ripples in this rectified voltage rather than to actually convert an AC voltage that's swinging from +ve to -ve to a DC voltage.  Therefore polarised caps should be ok.

Having said all that, wait for Tony HB or someone to back me up (or otherwise) before you go blowing up any caps ;).

Jonny

On 18 Jan 2013, at 14:03, Marc Nostromo [M-.-n] wrote:

> I'm still slightly confused between polarized versus non polarised capacitors :)
> 
> I'm going to need a voltage regulator to bring down 9v to 5v with a
> LM7805 using this rough schematics
> 
> http://snesdev.antihero.org/wp-content/uploads/2008/03/lm7805.gif
> 
> I undestand the capacitors are used to stabilize the ac changes in the
> DC supply. Does that mean I can't use polarised caps ?
> 
> Because my impression is that the voltage will no matter what be
> higher than the ground so polarity should not get in the way.
> 
> Does all that make sense ? :)
> 
> Thanks
> Marc.