The superposition principle states that the voltage across (or current through) an element in a linear circuit is the algebraic sum of the voltages across (or currents through) that element due to each independent source acting alone.
The principle of superposition helps us to analyze a linear circuit with more than one independent source by calculating the contribution of each independent source separately. However, to apply the superposition principle, we must keep two things in mind:
1. We consider one independent source at a time while all other independent sources are turned off. This implies that were place every voltage source by 0 V (or a short circuit), andevery current source by 0 A (or an open circuit). This way we obtain a simpler and more manageable circuit. Other terms such as killed, made inactive, deadened, or set equal to zero are often used to convey the same idea.
2. Dependent sources are left intact because they are controlled by circuit variables. With these in mind, we apply the superposition principle in three steps:
