The current conveyors (CCIIs) operate linearly under certain conditions. Violation of these conditions causes nonlinear distortion in active filters involving CCIIs. On the other hand, voltage-mode active-PC filters are considerably important in filter design. Considering these facts, a simple formula is derived for maximum input signal amplitude preventing nonlinear distortion in voltage-mode active-RC filters involving current conveyors. Derived formula are verified by SPICE simulations on chosen active filter examples. Using the formula presented in this study and the impedance scaring property, the input signal level can be optimized and the behaviour of the active filters can be improved. (C) 1998 Elsevier Science Ltd. All rights reserved.