ABSTRACT
This chapter presents the analysis of basic alternating current (a.c.) parallel electric circuits containing impedances and ideal a.c. supplies. It aims to understand how power factor may be improved. The parallel resonant circuit is often described as a rejector circuit since it presents its maximum impedance at the resonant frequency and the resultant current is a minimum. Electrical resonance for the parallel circuit can be likened to a mass hanging on a spring which, if pulled down and released, will oscillate up and down but due to friction the oscillations will slowly die. Currents higher than the supply current can circulate within the parallel branches of a parallel resonant circuit, the current leaving the capacitor and establishing the magnetic field of the inductor, this then collapsing, and recharging the capacitor. Single-phase parallel a.c. circuit theory is of great importance in electrical/electronic engineering.
