🚀 go-pugleaf

On Jun 10, 4:26 pm, rebel <m...@privacy.net> wrote:
> On Tue, 10 Jun 2008 06:36:46 -0700 (PDT), MooseFET <kensm...@rahul.net> wrote:
> >On Jun 9, 6:32 pm, rebel <m...@privacy.net> wrote:
> >> On Mon, 9 Jun 2008 07:55:58 -0700 (PDT), MooseFET <kensm...@rahul.net> wrote:
> >> >On Jun 9, 5:42 am, F Murtz <hagg...@hotmail.com> wrote:
> >> >> I would like to make an adjustable power supply using a transformer with
> >> >> a 24v 5a single wound secondary I would like the voltage to be
> >> >> adjustable from lowest to highest possible given transformer I would
> >> >> like to have regulated current
>
> >> >> There is another possibility I also have a larger transformer with two
> >> >> 32v 4.7a secondaries If anyone has a schematic for an adjustable power
> >> >> supply with adjustable current regulation making the most of the
> >> >> transformer specs I would be eternally grateful
>
> >> >How much current do you want?
>
> >> >Lets just assume you make DC from the AC and then regulate down.
>
> >> >Doing a couple of figures for making 4A into lets say zero volts:
>
> >> >24V * sqrt(2) = 34V
>
> >> >34V * 4A = 136W
>
> >> >The the regulator circuit needs to get rid of 136W.
>
> >> Minor points - the transformer isn't rated to deliver 136W, and that 34V is
> >> unloaded peak.
>
> >When working out the power in the regulator, it is best to assume that
> >the peak voltage is what you get.  The rated voltage on the
> >transformer is for a normal line voltage.  In the high line case, you
> >can get a little more.
>
> I appreciate that, but my original comments stand.  There is no valid reason to
> state "the regulator circuit needs to get rid of 136W" when the transformer is
> not rated to deliver that power.

You seem to have a poor understand of what the rating of a transformer
means.