Hello eric
Can you tell me why i need a 12V supply to the op amp?cant i work with a 5V supply?
hi Suraj,
The opa requires about a 2volt overhead so that it can drive upto +5V [which is about 102Cdeg]
A +8V or +9Vdc would be OK for 100Cdeg.
If you only wish to measure upto about +60Cdeg max,[thats +3V out] then a +5V supply would be OK.
Most simple opa's are not rail to rail, that is they cannot swing from 0V thru +Vsupply, they need a 2V overhead.
The CA3140 can swing with about +10mV of 0V and to a high of [Vsupply -2V].
Do you follow OK.?