[sdiy] Resistors in feedback loop of noninverting op amp buffer

[Aaron Lanterman]

Every once in a while, I see something that's clearly a unity gain  
noninverting op  buffer, but the designer has put a resistor in the  
feedback loop. There's no resistor from the negative input terminal to  
ground, so it's not like they're trying to provide gain. All the  
textbooks show a wire from the output to the negative input terminal.

Why do people sometimes put a resistor there? When inputting  
schematics into Eagle I keep wanting to just replace them with wires,  
but I don't want to do that if there's a good reason they are there.

- Aaron