This paper proposes two generalised instrumentation amplifier topologies which can operate in voltage, current, transadmittance, and transimpedance mode. Each topology is a two stage structure, wherein an amplifier is used as first stage in the first topology and a converter is employed in the second one. The second stage is difference amplifier for both the structures. The theoretical proposition is verified through operational floating current conveyor (OFCC). The effect of non-idealities of OFCC on system performance, in particular finite transimpedance and tracking error, is also analysed and corresponding mathematical formulation is presented. The functional verification is performed through SPICE simulation using CMOS-based implementation of OFCC. The experimental results using current feedback operational amplifier-based OFCC implementation are also included which are in close agreement with theoretical and simulated results.