Natural and Step Responses for RLC Circuits The natural and step responses of RLC circuits are described by second-order, linear diﬀer-ential equations with constant coeﬃcients and constant “input” (or forcing function), a d2x dt2 +b dx dt +cx(t)=D, (1) where a,b,c, and D are constants, and the initial values x(0+)anddx(0+) dt are known ... Drawing a phasor diagram for a series circuit: We plot the values of voltage and current on individual components in the AC circuit into the phasor diagram. The current is of the same size on all the components, the phasor of current I m is therefore the same for all the components and is usually drawn in the positive direction of the x -axis. RLC, RL, RC & LC Circuits Impedance Calculator getcalc.com's RLC Circuit Equivalent Resistance (Z eq ) Calculator is an online electrical engineering tool to calculate resultant resistivity for resistor (R), inductor (L) & capacitor (C) connected in series or parallel. The Series RLC Branch block implements a single resistor, inductor, or capacitor, or a series combination of these. Use the Branch type parameter to select elements you want to include in the branch. Negative values are allowed for resistance, inductance, and capacitance.