Hello,
I created a low pass filter in orcad and trying to put theory into pratical. The circuit output is always showing the input at about one third the pk-pk voltage even at 30kHz and more, this is suppose to be a 3kHz lpf.. I think the wiring might be wrong. I took the black pin of the function generator as the ground reference point. Use two 6v batteries for positive and negative voltage and place the middle of the batteries at the ground reference point from the function generator. Here is a link with my circuit and a picture: