[GreenKeys] Looking for components to build loop supply

[John Nagle]

>> 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 

Here's my RS-232 interface for 60mA current loops:

http://www.animats.com/nagle/aetheric/connecting.html

I've built two of these, and someone else built one.  They
seem to work.  You need a PC with a traditional serial port,
though; USB to serial converters mostly won't go 45.45 baud.

Halted Specialties has some surplus 120VDC 200mA open-frame linear
regulated power supplies, and I've been using those.

If someone is really ambitious, I have a SPICE model for a 60mA
current loop driver designed to drive Model 15 selector magnets
off a 5V 250mA supply.  I'd been designing a device
to connect USB to 60mA current loop without an external power
supply.  It's quite possible, but the number of people who need one
is rather small.

					John Nagle