[GreenKeys] Looking for components to build loop supply

[Bill Henry]

Do it the easy way. Get two identical filament transformers and hook 
them back-to-back.  You'll then have 120 VAC, isolated from the power 
line.  Should be able to get them for less than $10 - at a hamfest or 
surplus outlet.  Half-wave rectify with 100 uF cap and you'll have 
about 85-100 VDC.  Full-wave bridge rectify and get maybe 175-200V. 
The exact voltage is not critical, just set the current to 60 mA with 
a series resistor.  Swicth the loop with an MJE-340 or 2N5655.
Bill Henry

At 02:29 PM 7/31/2009 -0400, John D. Kopke wrote:



> > Yeah, I know this is easy . A 150 v dc xfmr, resistor and a 
> rheostat.I could use
> >just the components to build one if any one has them laying around 
> or leads on
> >where to get them. I am trying to build an RS-232 converter for 
> the "Tempest"
> >Dovetron. I've been looking through the mouser catolog but start 
> to go cross-eyed
> >after page 50! Thanks in advance for any help. Best to all
> >
> >
> >
>
>
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