I added negative feedback to ver. 3 ( http://everycircuit.com/circuit/5297918833065984 ).
This got little bit complicated, I extracted a half part of this ( http://everycircuit.com/circuit/6613488723558400 ).
In real, I can make a negative feedback connect to a pre-amplifire for increasing the voltage directly. Then I don't have to use an additional operational amplifire.
