device showing the connection to sense current in an external wire.
But being a "current" device, you need to convert it into a large enough voltage to drive a LED. So here's the ckt config to do that. Any "SINGLE RAIL" opamp will work in this ckt.
The web site;
http://www.gmw.com/electric_current/Sentron/CSA-1.html Click on the 'accessories' to see the
AN-109KIT.