Power spectra and return maps of nonlinear dynamic response of KH2PO4(KDP) crystal near ferroelectric transition temperature T-c in the RLC circuit are obtained to confirm period-doubling, Hopf bifurcations, quasiperiodicity and locking. Attempts are made to explain the experimental observations in terms of the Duffing oscillator solutions of the nonlinear RLC circuit, where C represents the nonlinear capacitance of the KDP crystal near T-c