Alternating Current

RCL Series Circuits

Phasor Diagrams


It is important to note that at any given time, the sum of the voltages across the three components, R, C, and L, must equal the voltage of the AC source. This is just energy conservation or Kirchoff's Loop Rule,

v(t) = vR(t) + vC(t) + vL(t)


v = vR + vC + vL

However, a similar equation for the rms values or the maximum values of these voltages would not be true. That is,

V VR + VC + VL


Vo VR,max + VC,max + VL ,max

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(c) Doug Davis, 2002; all rights reserved