🚀 go-pugleaf

On Sat, 14 Jun 2008 07:48:55 -0700 (PDT), MooseFET <kensmith@rahul.net> wrote:

>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.

On the contrary.  A 24V 5A secondary is rated for 120VA.  Your education
suggests something different?  Please inform us all as to YOUR transformer
theory.