🚀 go-pugleaf

On Tue, 10 Jun 2008 06:36:46 -0700 (PDT), MooseFET <kensmith@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.