Output offset: dual supply opamp running on single supply

operational-amplifierprecision-rectifier

I'm running a precision rectifier circuit on TL082. http://www.ti.com/lit/ds/symlink/tl082-n.pdf
supplying dual supplies (+/-12V) has it working correctly, however a single supply(0-12V) does not. I'm guessing that the asymmetrical supply has ground at midrail, or 6v. However, offsetting the input does not correct behaviour. I'm sure there is something simple I don't understand here.
circuit

Best Answer

Every time you take the input voltage higher than 0V you are "asking" the op-amp to produce a negative output voltage - this circuit is an inverting precision rectifier - it is trying to make a negative voltage on the output follow the positive voltage on the input. With no negative supply it doesn't work. With a positive bias and no negative supply it doesn't work.

Try a negative bias on the input or a positive bias on the non-inverting input.

Alternatively swap the diode directions and let a positive rectified output from the op-amp properly follow a negative half cycle on the input.