Vector Diagram for a Series RC Circuit - Wisc-Online OER Vector Diagram for a Series RC Circuit By Terry Bartelt. Learners view a vector diagram for a series RC circuit and read information concerning the voltage across each component, the What is RC Series Circuit? Phasor Diagram and Power Curve Power in RC Series Circuit; Waveform and Power Curve of the RC Series Circuit; Phasor Diagram of RC Series Circuit. The phasor diagram of the RC Series circuit is shown below. Steps to draw a Phasor Diagram. The following steps are used to draw the phasor diagram of RC Series circuit. Take the current I (r.m.s value) as a reference vector Parallel RC Circuit | Phasor Diagram | Impedance & Power Figure 1 Parallel RC circuit. Parallel RC Circuit Phasor Diagram. The relationship between the voltage and currents in a parallel RC circuit is illustrated in the vector (phasor) diagram of Figure 2 and summarized as follows: The reference vector is labeled E and represents the voltage in the circuit, which is common to all elements.