From: Ryan Underwood (nemesis-lists_at_icequake.net)
Date: 2004-01-18 20:15:33
On Fri, Jan 16, 2004 at 01:43:26AM +0200, Gianmario.Scotti@nokia.com wrote: > This seems almost identical to what I suggested, except it's > somewhat bad. Read my comments below. > > > -----Original Message----- > > From: email@example.com > > [mailto:firstname.lastname@example.org]On Behalf Of ext Ryan Underwood > > Sent: 16 January, 2004 01:06 > > To: email@example.com > > Subject: Re: C64 power supply replacement > > > > > > > > I had a design proposed to me by a friend; advantage is that it is > > easily built from Radio Shack parts but I would like some > > opinion on it. > > > > - Start with 120V / 12.5VAC transformer > Why not 9V AC secundary? Because I need parts I can easily get (read: at Radio Shack...) ;) > > - Use voltage divider to derive 9VAC from secondary and send that > Do you mean, a two-resistor voltage divider? I hope not. Yeah, such as: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/vdivac.html > > straight to the C64 (it needs no regulation, correct?) > > - perhaps a bridge rectifier on secondary? > > - Send 9VAC through a 7805 regulator set to 5V > > - Filter ripple from 5V with a RC pair > Actually, an RC pair would consume way too much energy. Same as the > voltage divider you mentioned previously. > > - Zener protection on regulator output to prevent short > > failure damaging C64 > Not necessary! The 7805 NEVER shorts. It's an incredibly > well-protected and well-protecting IC. I didn't know that. At least it seems like every other regulator in the world likes to pretend it is a wire at some times... BTW, I thought your design was simple and elegant, but I just took another angle at it (from the cost reduction standpoint). -- Ryan Underwood, <firstname.lastname@example.org> Message was sent through the cbm-hackers mailing list
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