jumbo

Hi all I am trying to build a basic phototransistor circuit. Objective: to sense small variations of light and translate them to a voltage variation. I have seen many circuits on the internet, and none shows where the base is connected to?? already got a phototransistor, and it got 3 pins (B-C-E), so where should i connect the base to?? Plus, does any of you have a nice circuit that can be useful to me? Because it is the first time i deal with phototransistors... Any help would be apreciated... NB: please keep in mind that im trying to build a sensor that can detect SMALL variations of light... Thank you.