Introduction to Potentiostats - why do we need them and how do they work? 

Basic but essential to know !

Thank you for this great explanation, and I appreciate very much the inclusion of the explanation of why use a three-electrode system! One comment/question: In the diagram that you provide you connect the reference electrode directly to the inverting terminal of the OpAmp. But, then, I think that the feedback voltage is the reference electrode's constant voltage, not the changing working electrode's voltage. I think I understand now from piecing a few different videos together that there should be a low-gain differential OpAmp that outputs the difference between RE and WE, and then that differential output is fed into the feedback.