Question
The OP184 has two offest nulling pins. What resistance should the nulling
potentiometer have, and where is its slider to be connected to?
Answer
For offset adjust, use a 20K resistor between offset null pins 1 and 5 with the
wiper to the negative terminal. The null range is +-1mV which is good for this
part.
One thing you need to be aware of is that this is the Null at mid point. The
rail to rail inputs have a trip point where the NPNs and PNPs switch and the
offset is the highest. So even if we null at 0 common mode, the offset changes
with common mode.