[GreenKeys] Basic Loop supply

[ken Schwieker]

Also insurance from inadvertently turning pot to point excessive 
current fries selector magnets. I know someone (not me) that connected wire to
wrong lug on pot, turned pot to max resistance (he thought) and 
plugged in supply.

Ken S

 >It also doesn't have to be adjustable from 0 to 2.5K - for example you can
 >use a high wattage fixed resistor like
 >http://www.digikey.com/product-detail/en/riedon/UAL10-2KF8/696-1492-ND/3886624 

 >or 
http://www.digikey.com/product-detail/en/yageo/SQP10AJB-2K0/2.0KW-10-ND/18789
 >in series with a smaller variable resistor which at 500 ohms would dissipate
 >no more than 1.5W at 60mA.  May not provide sufficient adjustment range, but
 >it could at least offload the expensive part of the job to a 
cheaper fixed resistor.
 >
 >eric