ABSTRACT
This chapter provides the reader with an introduction to the behaviour and application of resonant circuits. More complex circuits, containing both types of reactance together with resistance, are described as ‘resonant’ since there will be one frequency at which the two reactive components will be equal but opposite. SCILAB's graph plotting functions can be put to good use to investigate the behaviour of a series resonant circuit above and below resonance. The impedance of a series resonant circuit takes its lowest value (equivalent to the series resistance present in the circuit) at resonance. As the Q-factor of a resonant circuit increases, the frequency response curve becomes sharper. Loading of a series tuned circuit occurs whenever another circuit is coupled to it. The goodness of a resonant circuit in terms of the sharpness of its frequency response and its ability to magnify voltage or current is expressed in terms of its Q-factor.
