Comments on "A CMOS fully balanced four-terminal floating nullor

For original paper see ibid., vol.49, p.413-424 (2002 ). The comments in the present paper state that the four-terminal floating nullor (FTFN) is not more versatile than the CCII, because any circuit can also be realized with CCIIs as the only active elements, and that the FTFN and the CCII are not the only universally versatile elements. There are others, such as operational amplifiers. The authors of the original paper state that the FTFN is not yet commercially available. One counterexample is the MAX 435 by Maxim. There are others as well. None of the commercially available FTFNs have actually been given the name "nullor," which may be the reason why few people seem to know of the commercial availability of FTFNs.