The Superposition Theorem is specifically applicable to linear systems. Here's a detailed explanation:
### **Superposition Theorem**
**Definition:**
The Superposition Theorem states that in any linear circuit with multiple independent sources (voltage or current sources), the response (voltage or current) at any component can be found by considering the effect of each independent source separately and then summing these effects.
**Mathematically:**
If you have a circuit with sources \( V_1, V_2, \ldots, V_n \), the total voltage across or current through any component is the sum of the voltages or currents due to each source acting individually, with all other sources turned off (replaced by their internal resistances, which for ideal voltage sources is a short circuit and for ideal current sources is an open circuit).
**Steps to Apply Superposition Theorem:**
1. **Turn off all independent sources except one**:
- Replace voltage sources with short circuits (i.e., connecting their terminals directly).
- Replace current sources with open circuits (i.e., removing them from the circuit).
2. **Analyze the circuit with the single active source**:
- Calculate the contribution of the single active source to the voltage or current in the circuit.
3. **Repeat the process for each independent source**:
- For each independent source, turn off all other sources and calculate the contribution of that source.
4. **Sum the contributions**:
- Add up all the individual contributions from each source to get the total response.
### **Applicability to Linear vs. Nonlinear Systems**
- **Linear Systems**: The Superposition Theorem is valid and very useful. Linear systems obey the principle of superposition because their responses are directly proportional to the input. This means that if you have a linear circuit, you can safely use the theorem to find the total response.
- **Nonlinear Systems**: The Superposition Theorem does not apply. Nonlinear systems do not have a response that is directly proportional to the input, and the interactions between multiple sources in such systems can lead to complex behaviors that cannot be decomposed into simple linear contributions. In nonlinear circuits, the response to multiple sources cannot be obtained by summing the responses due to each source acting alone.
### **Examples**
- **Linear Circuit Example**: For a simple resistor network with multiple voltage sources, you can apply the Superposition Theorem to find the voltage across or current through any resistor by considering the effect of each voltage source individually, as described above.
- **Nonlinear Circuit Example**: In a circuit containing diodes or transistors operating in their nonlinear regions, the Superposition Theorem cannot be used directly. The nonlinear elements mean that the circuit's overall behavior cannot be expressed as a simple sum of the effects of individual sources.
### **Summary**
The Superposition Theorem is a powerful tool for analyzing linear circuits, allowing for a systematic approach to finding the effect of multiple sources. However, it is not applicable to nonlinear circuits due to the complexity introduced by the nonlinearity.