Realisation of linear voltage-controlled resistance in floating form

A number of FET-based configurations have been described in the literature that realise linear voltage-controlled resistors (VCRs) in grounded form. However, there are many situations where a linear VCR is needed in floating form. The author considers the realisation of floating linear VCRs (FVCR) which leads to the evolution of a novel low-component-count configuration making it possible to realise a floating as well as grounded VCR both from the same structure with exactly the same number of active and passive elements (i.e. a single opamp, one FET and five resistors). The validity of the proposed formulation has been verified experimentally