RLC Circuits

Ohm for AC  An AC circuit is made up with components. Power source Resistors Capacitor Inductors  Kirchhoff’s laws apply just like DC. Special case for phase R C L

Series RLC  A series RLC circuit can be made from each component. One loop Same current everywhere  Reactances are used for the capacitors and inductors.  The combination of resistances and reactances in a circuit is called impedance. R v L C i

Vector Map  Phase shifts are present in AC circuits. +90° for inductors+90° for inductors -90° for capacitors-90° for capacitors  These can be treated as if on the y-axis. 2 D vector2 D vector Phasor diagramPhasor diagram V L =IX L V C =IX C V R =IR

Vector Sum  The current is the same in the loop. Phasor diagram for impedancePhasor diagram for impedance  A vector sum gives the total impedance. XLXL XCXC R XLXL XCXC R Z

Vector Sum XLXL XCXC R Z  The total impedance is the magnitude of Z.  The phase between the current and voltage is the angle  between Z and the x-axis. 

Phase Changes  The phase shift is different in each component.

Power Factor  Power loss in an AC circuit depends on the instantaneous voltage and current. Applies to impedanceApplies to impedance  The cosine of the phase angle is the power factor. t0 P next