The IR drop in three-electrode systems was automatically compensated by the use of an electronic unit, which was easily made up of an analogue multiplier and some electronic circuits. The present method is based on the positive feedback technique, which has often been used because of its simplicity and practical use. The potentiometer in the positive feedback circuit was replaced by the electronic unit. It was applied to the following electrode systems: (1) a Cd2+ + DME in KNO3 system and (2) a Cd2+ + DME in nitrilotriacetic acid (NTA), acetate buffer and KNO3 system. It achieved real-time and adaptive IR compensation, which was not influenced by the increase of the area of the DME at scan rates up to 1000 V s-1. The amplitude of the input voltage was 1.0 V peak-to-peak. It also has the advantage of simple operation which does not require any troublesome preadjustment of the initial values of the feedback circuit in the potentiostat. © 1992.