As demonstrated in the paper, chaotic motion can appear in state variable filters, that is, common network structures dedicated for analog signal processing. In particular, two Kerwin-Huelsman-Newcomb biquadratic filtering sections are considered for theoretical, numerical and experimental analysis. Mathematical models are designed, and conditions for evolution of typical strange attractors are provided. The corresponding largest Lyapunov exponent is calculated and visualized as a function of internal system parameters and the shape of input harmonic waveform. Mutual connection between the mathematical model and the real lumped electronic circuit is discussed in detail. Copyright (C) 2016 John Wiley & Sons, Ltd.