Various ITER relevant experiments using 3He in a majority D plasma were performed in the recent JET campaigns. Two types can be distinguished: dedicated studies of the various RF heating scenarios which rely on the presence of 3He, and physics studies using RF heating as a working tool to provide a tunable heat source. As the success of a number of these experiments depended on the capability to keep the 3He concentration fixed, real time control of the 3He concentration was developed and used. This paper presents a brief overview of the results obtained, zooms in on some of the more interesting recent findings and discusses some of the theoretical background.