Rockbox mail archiveSubject: Re: [Sven.Radke_at_gmx.de: battery faq]
Re: [Sven.Radke_at_gmx.de: battery faq]
From: Uwe Freese <mail_at_uwe-freese.de>
Date: Sun, 8 Sep 2002 16:03:33 +0200
Björn Stenberg wrote on Sunday, September 8, 2002, 3:05:52 PM:
BS> > A good circuit for powering from a car battery or other source
BS> with a higher voltage would be a 600 mA fuse and a 9V regulator like
BS> a 7809 of your favourite manufacturer in series.
BS> it's that if u use just a 7809 the voltage is about 8 volts, I
BS> experienced it 2 times (1 a while ago but I remembered when the 2nd
BS> spit out just 8 volts)
BS> the 7809 needs a lil buffering the energy, I made this witch adding a
BS> 470uf/25V condensator to input and output
I think the problem is that one should use a low drop voltage regulator.
A standard one needs 2-3 volts more input than output voltage. And maybe
his car battery had less than 12 volts.
But it is useful to have something like a 470uf/25V connected in any
Received on 2002-09-08