Hello everyone, i am currently having the same problem. My op amp isn't generating negative part of the square wave coming from the sound port of my computer. Infact, although sounding ridiculous, i am using an analog multimeter to measure this and at 1Hz i don't see the needle staying at, lets say, 5V. It only changes in positive going tick (PGT) and goes to zero. You would probably say i shouldn't be using the signal generator form my comp but in any case can you explain why this is happening. Also how can i get my op amp to generate the negative part of my square wave? i am using inverting config with R2= 100,000ohms with R1=100ohms for maximum gain (gives me 0.7v input to 6v output) however going R2=1,000,000 ohms gives me 1v, i don't understand why.

I Also, you will need to bias the non-inverting input at 2.5V. This can be done with two 10K resistors forming a voltage divider assuming you are going to use 5V for the op amp supply

mik3, can you please post a circuit diagram of that and elaborate on what you mean by baising the non inverting input and why do you need to do that.

 

This is called, "hijacking a thread". You're supposed to start your own question.

 

This has been moved to its own thread. The original - http://forum.allaboutcircuits.com/showthread.php?t=37913

Either you need to bias the signal so no part of it goes negative, or give your op amp a negative voltage supply.

 

This thread is a duplicate of this one:
http://forum.allaboutcircuits.com/showthread.php?t=37919

As the other thread has received multiple replies and the OP has posted their schematic, this thread can be closed.