The foundation of circuit analysis is Kirchhoff's Laws for current and voltage. We have the fundamental set of tools required to begin evaluating circuits with these two principles, In an RLC circuit, the most fundamental elements of a resistor, inductor, and capacitor are connected across a voltage supply.
Only if all of the voltages are in phase with one another will the sum of the voltages around the circuit equal the applied voltage. However, in LCR circuits, the voltages across various components won't always be the same.
The phasor diagrams used throughout the chapter demonstrate that the voltages are added in a vector form rather than a scalar form. Although the voltages across various circuit elements are never concurrently at their highest values, Kirchhoff's loop rule is always true. Remember that an inductor has an emf that it can produce on its own and that the voltage across it is 90 degrees in front of the current in the circuit. Kirchhoff's Laws describe current in a node and voltage around a loop. These two laws are the foundation of advanced circuit analysis
