USE: Adjust the top (trimmer) potentiometer to set reference voltage.
Adjust bottom pot for the tracking regulator.
(1k resistors on the right are just there to simulate an output load)
The Vref is used as the negative supply for one op amp.
(The inverting Vref is not actually used here.)
Description:
This is just an ultra simple and primitive op amp tracking regulator (or I guess I should say "tracking reference" as this lacks an output stage).
This is similar to the tracking regulator listed in the 3rd edition of "The Art of Electronics." The one in the book uses a couple of OPA27's, a 1.25v reference, and a LM317/LM337 to create a simple adjustable tracking regulator. I built something similar, but I have a bunch of TL431's and LM358's. I don't care if it's super accurate. I just wanted something quick and easy to use on a breadboard with op amps.
I am simply using a 2.5 Vref and resistor divider to create a 1.25v and -1.25v offset voltage to get the 317/337 to adjust to zero volts. IRL and here I have used a 20k pot to adjust the reference and dial in the output of the op amps to the desired voltages.
