Re: linear PS's
- From: Mike <nomtrxspam@xxxxxxxxxxx>
- Date: Tue, 31 Jan 2006 06:32:36 -0500
<snip>
>
>I suggest you use the center tap of the secondary as common, with a
>bridge rectifier across the 40 volts. Connect 2 storage capacitors in
>series, with the positive end of one to the + output of the bridge and
>the negative of the other to the - output of the bridge.
and the junction of the 2 caps to the center tap of the transformer
which will be your common or ground.
> This should give you about positive and negative 28 volts, no load.
It cuts your max output voltage in half but gets you the + and - you
want.
>Your LM317 regulator is fine for the positive output (with the reference divider
>to the center tap). You need the negative version of the 317, and
>LM337, for a symmetrical negative regulator.
>
>> One more thing... I was messing around monitoring the voltage and the
>> output(of the regulator) seemed to fluxuate with 1/100th of a volt or 2 and
>> at some points it was about 1/2 a volt or so. Is this normal? (I wasn't able
>> to monitor the input voltage at the same but it seems to fluxuate too).
>
>Do you have a high frequency bypass capacitor (e.g. .1uF 50 V ceramic)
>connected directly from the grounded end of the reference divider to
>the regulator input, and a second one from the common to the regulator
>output? If not, you may have an oscillating regulator.
.
- References:
- linear PS's
- From: Abstract Dissonance
- Re: linear PS's
- From: John Popelish
- linear PS's
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