The Thvenin theorem is a network theorem in electrical engineering that states any linear circuit can be replaced by an equivalent circuit consisting of a voltage source in series with a resistor. This equivalent circuit is known as the Thvenin equivalent circuit and has the same voltage-current relationship at the output terminals as the original circuit. To find the Thvenin equivalent circuit, the original circuit is simplified by removing the load resistance and determining the open-circuit voltage and internal resistance at the load terminals.
The Norton theorem is another network theorem that states any linear circuit can be replaced by an equivalent circuit consisting of a current source in parallel with a resistor. This equivalent circuit is known as the Norton equivalent circuit and has the same voltage-current relationship at the output terminals as the original circuit. To find the Norton equivalent circuit, the original circuit is simplified by removing the load resistance and determining the short-circuit current and the equivalent resistance at the load terminals. The Norton theorem is often used in the analysis of circuits with multiple sources and complex configurations.
Superposition is a principle that states in a linear circuit with multiple sources, the response at any point can be determined by considering the individual effects of each source acting alone while all other sources are turned off. This means that the total response is the sum of the responses due to each individual source. Superposition can be used to simplify the analysis of complex circuits and is based on the linearity property of linear circuits.
The main limitation of using network theorems is that they can only be applied to linear circuits. This means that the components in the circuit must follow Ohm's law and have a linear voltage-current relationship. Non-linear components, such as diodes and transistors, cannot be analyzed using network theorems. Additionally, network theorems assume ideal conditions, such as no parasitic effects or perfect components, which may not always hold true in real-world circuits.
Network theorems are used in practical circuit analysis to simplify complex circuits and make it easier to determine the voltage and current at specific points in the circuit. They can also be used to design circuits and determine the best component values to achieve a desired output. In addition, network theorems are often used in computer-aided circuit analysis software to simulate and analyze circuits quickly and efficiently.