Re: DC switching circuit?
i did some this sort of project in my bachelors...so
u can use WINDOW comparator, using OP-AMP as a decision between ur voltages, and adjustments using variable resistors..
then ur required switching can be done using andy contactor (relay) operating on +5 volt...
for isolation between ur comparator and relay u can use opto-isolator (4N25 or 4N35)...
i think this whole of ur project... u just have to implement it...
if have problems, then discuss..
Regards..
Naveed