4 diodes for a typical full wave bridge rectifier...
From: Rob Danielson
Sent: Thursday, August 26, 2004 8:23 AM
Subject: Re: [Nature Recordists] My Audio Buddy problem.
At 3:05 PM +0000 8/26/04, Dave J wrote:
>Ok Rob, this looks pretty simple, and that's a
>pretty fine photo you took. I still can't quite
>follow the diode connections but it looks like
>they have them connected to produce a positive
>and negative on the input of the two linear
>regulators. I'm not quite sure why they have four
>diodes since this would be a half-wave rectifier
>circuit. Maybe two are connected as protection
>diodes? Are those pairs of electrolyic caps
>connected in parallel?
>Do you have a DMM/voltmeter?
Yes, but no time, Dave. I have a big project due and classes
starting. I can make it to UPS some time after next Tuesday,.. Rob D.
= = = = =
"Microphones are not ears,
Loudspeakers are not birds,
A listening room is not nature."
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[Non-text portions of this message have been removed]
>From Tue Mar 8 18:27:39 2005
Date: Thu, 26 Aug 2004 16:01:27 -0000
From: "Rich Peet" <>
Subject: Re: My Audio Buddy problem.
Well if it worked with +- 18 volts then I was wrong and it looks like
2 voltage doublers. One for each rail. That can be done with the 4
diodes and 4 caps. The numbers on the voltage regulators would give
the info to conclude that. The problem then would stay the same as
the mod he already did. It will take too many batteries to fire it
up and you end up building a complete dc to dc supply for it.
--- In "Dave J" <>
> Well there must be something tricky in there
> somewhere if it turns 9 VAC into 48 VDC. Maybe
> this is a voltage quadrupler circuit?
> Do we know for a fact that a cheap 12VDC to 120VAC
> inverter is not a good solution?
> --- "Rich Peet" <> wrote:
> > Looking at the photo more I don't understand
> > why it will not work on dc. You just need to
> > supply the correct polarity at 2.5 volts over
> > the output of those regulators. The 4 digit
> > number on the regulator chips will tell you
> > the voltage out of them and just add 2.5 to 5.0
> > volts. I also don't see that it would hurt it
> > to supply the wrong polarity other than to make
> > it not work.
> > Are you sure you supplied the correct polarity
> > when you tried it on dc?
> > Looks like a simple full wave bridge conversion
> > from ac to dc. filtered with just 2 large caps
> > on both the + and - sides. then the outputs of
> > that go to the two regulators.
> > Rich