So i found this post about voltage to current conversion. http://www.allaboutcircuits.com/vol_3/chpt_8/7.htmlhttp://www.allaboutcircuits.com/vol_3/chpt_8/7.html It talks about how to convert 1-5V to 4-20mA which is exactly what I am trying to do. I have attached the circuit which I am referring to. I have a small question which well, might be a bit dumb but please help! Can I use an op-amp such as LM741 from TI in this circuit or is that amp some special kind of amp? Please help.