Frequency-Domain Analysis of Non-Linear Circuit Elements HORIA ANDREI Faculty of Electrical Engineering University Valahia Targoviste 18-20 Blv. Unirii, Targoviste, Dambovita ROMANIA FANICA SPINEI Faculty of Electrical Engineering University Politehnica Bucharest 313 Splaiul Independentei, sector 6, Bucharest ROMANIA Email: spinei@elth.pub.ro http://www.elth.pub.ro COSTIN CEPISCA Faculty of Electrical Engineering University Politehnica Bucharest 313 Splaiul Independentei, sector 6, Bucharest ROMANIA http://www.elth.pub.ro VALENTIN DOGARU Faculty of Electrical Engineering University Valahia Targoviste 18-20 Blv. Unirii, Targoviste, Dambovita ROMANIA Email: dogaru@valahia.ro http://www.valahia.ro SORIN-DAN GRIGORESCU Faculty of Electrical Engineering, University Politehnica Bucharest 313 Splaiul Independentei, sector 6, Bucharest ROMANIA http://www.elth.pub.ro NICOLAE JULA Military Technical Academy Bucharest ROMANIA http://www.mta.ro Abstract - This paper presents an alternative mathematical method for determining the spectrum of signal for the nonlinear elements in non sinusoidal steady-state regime. For illustration the time- domain analysis of nonlinear circuit components, are presented two numerical examples. 1. Introduction The larger use of the nonlinear elements of the electroenergetic networks, especially during the past decade, has drawn the specialists’ and researchers’ attention on problems such as to determine the behavior of the nonlinear elements in non-sinusoidal steady-state regime, to find the new spectrum of frequencies and magnitudes in this case. The analysis of the non-sinusoidal steady-state regime of the circuits is made using the Fourier transform, as in [1], [2], calculating the circuit for each harmonic. Proceedings of the 5th WSEAS Int. Conf. on Instrumentation, Measurement, Circuits and Systems, Hangzhou, China, April 16-18, 2006 (pp1-5)