[GreenKeys] my simple little loop supply ERIC AND GIL CONFER?

[Eric]

I didn't see the power supply in question in detail but using it with my
adapter board should just work. If the current gets too low, adjust the
resistance downward until it's back around 60 mA. My board will be fine
down to about 20mA but a real selector magnet probably won't. 

eric 

On 06/29/2016 9:38 pm, COURYHOUSE at aol.com wrote: 

> Eric and Gil... 
> 
> ok I want to use the power supply gill mentions here looks good but want to use with Eric's board which as one resistor on board? Ok is it ready to fly or do I need to change resistance value. 
> 
> Thanks in advance for shared wisdom! 
> 
> Ed# www.smecc.org 
> 
> In a message dated 6/28/2016 2:20:51 P.M. US Mountain Standard Time, greenkeys at mailman.qth.net writes: 
> In a message dated 6/28/2016 2:14:02 P.M. US Mountain Standard Time, gil at baudot.net writes: 
> So I went to test my M15 yesterday, but left my tty-connect at the office. Needed a quick loop supply. 
> 
> I had picked up a dandy little 48V switching supply and 800-ohm 5W resistor some time ago, but had not tried it out yet. Dug out those parts, found a Bud case that was lying around, cut the end off an extension cord (poked it through a cut-out), and found a 1/4" mono jack on a cable (poked that through a hole), and the entire thing is isolated in a plastic box with no need for line ground. Resistor burns about 3 watts, switcher pretty negligible, so no need for cooling holes really. No AC jack or switch, or even a light -- about as simple as it gets. 
> 
> The switcher has a trimpot to adjust from about 40V to 56V, so setting 60mA for various setups should be no problem. Could add a hole in the end panel for a diddle-stick. 
> 
> I think just 48VDC is plenty for most machines (provided you keep your keyboard contacts clean). Seems to work very well (you could use two for 96V). 
> 
> 48V supply (< $14 each for a little enclosed 48VDC, 0.57A switcher that does 115/230-in): 
> http://www.mouser.com/Search/ProductDetail.aspx?R=RS-25-48 [1] 
> 
> 800-ohm 5W resistor (just over a buck) for 60 mA loop: 
> http://www.mouser.com/Search/ProductDetail.aspx?R=25J800E [2] 
> 
> gil

 

Links:
------
[1] http://www.mouser.com/Search/ProductDetail.aspx?R=RS-25-48
[2] http://www.mouser.com/Search/ProductDetail.aspx?R=25J800E
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