From: pallison49@gmail.com   
      
   Peter Percival wrote:   
   >   
   > Phil Allison wrote:   
   > > Ralph Mowery wrote:   
   > >   
   > >   
   > >>   
   > >> All of that is well and good.   
   > >>   
   > >> However, is that going to be peak, average, rms or just what that the   
   > >> origional question wanted.  Is there going to be a capacitor to smooth   
   > >> out the voltage, or is the full wave rectified DC going to be used ?   
   > >>   
   > >> Lots of unasked questions in the origional question.   
   > >>   
   > >   
   > >   
   > > ** The original Q is a pile of utterly ambiguous drivel.   
   > >   
   > > If Q posters would simply reveal the PURPOSE of their question, ambiguity   
   would disappear and useful answers become possible.   
   > >   
   > > But no, they want to play at being smart and be in control the answers by   
   NOT revealing any such damn thing.   
   > >   
   > >   
   > >   
   > > ....  Phil   
   >   
   > Oh dear.   
   >   
      
    ** Shit, somebody  actually took notice of my complaint - never happened   
   before.   
      
      
   > I am looking at Fig 3.6 on p 42 of Marston's /110 operational amplifier   
   > projects for the home constructor/.  The circuit depicted is that of a   
   > power supply delivering 3-30V at 0-1A.  It is to be supplied with "+40   
   > to 45V (unregulated)".  The text has nothing to say about where that   
   > comes from.   
      
   **But it is easy to infer that the author means a transformer isolated supply   
   of rectified AC with adequate smoothing for one or more electro caps - with 1   
   amp DC capacity and 43 volts average output under load and nominal house   
   supply voltage.   
      
      
   > I have decided to use a bridge rectifier attached to the   
   > secondary of a transformer with 240(ish)V primary; and I wish to know   
   > what secondary I need.   
   >   
      
   ** The transformer will need to have 2 amps AC capacity and a rated secondary   
   voltage of 32 volts AC. This will give about 47V DC off load dropping to 42   
   under full(1A)load. About 4700uF(63V) filter capacitance should be OK.   
      
      
   > The "2amps" in my OP was a guess of mine that if the PS delivers 1amp,   
   > then 2amps in would be more than enough.   
      
   ** But there was no way previously for us to know what the heck you were up to.   
      
      
   .... Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)