An useful modification of well known signal flow graph technique for the circuit synthesis is described in this paper in order to obtain the filters working in the current mode, with maximally variable parameters, namely characteristic frequency, quality factor, bandwidth and basic gain. Procedure is based on reciprocal conversion of the branch variables (V ->I and I ->V) with the adjustable conversion constants. The obtained structures are discussed in detail and then is described an example of current-mode multifunctional RC active biquadratic filter, what is today very popular analogue application. Theoretic assumptions are supported by experimental results using modern functional blocks CC II(-).