Hello, I'm trying to make a low pass filter (time const = 1 sec.) I don't need a steep skirt etc. The catch is that the output, when measured with a multimeter, needs to be within about .25mV of the input (for a normal range of temperatures around room temp.)
Initially, I just made a lowpass filter using a precision resister and a ceramic capacitor. Then I put a LM741, used it as a buffer and then tried to tune out any voltage offset using the circuit that is recommended on the datasheet (basically just a variable resistor.)
Well to make a long story short, the circuit didn't work out very well. There is a small voltage offset that is hard to get rid of, that is different at different inputs.
Does anyone have any ideas for a good circuit that serves the purpose that I'd like it to. Thanks!