Look at these sites, maybe it'll help explain them:

http://www.associatedequip.com/assoc...als/mt326c.pdf
http://www.electrical-test-benches.c...equipment3.htm
http://www.tpub.com/content/construc...s/14273_46.htm
http://www.geocities.com/flywheels2001/Growler.html

Dave Young