The theorem is applicable to linear networks (time varying or time invariant) consisting of independent sources, linear dependent sources, linear passive elements (resistors, inductors, capacitors) and linear transformers. Superposition works for voltage and current but not power.

When can superposition theorem be applied?

If a circuit is made of linear elements, we can use superposition to simplify the analysis. This is especially useful for circuits with multiple input sources. To analyze a linear circuit with multiple inputs, you suppress all but one input or source and analyze the resulting simpler circuit.

What are the condition for applying superposition theorem?

All the components of the circuit must be bilateral, meaning the current will remain the same for opposite polarities of the source voltage. Active components and passive components may be used. Active components are diodes, semiconductors, transistors etc. Passive components are resistors, inductors, capacitors etc.