According to Kirchhoff's current law, the sum of all currents entering the node is equal to the sum of all currents leaving the node. As long as this law is satisfied, the nodes on both sides of the voltage source without series resistance can be regarded as a "big node" together with the voltage source, that is, a generalized node.
Kirchhoff's law is two basic laws in circuit theory, which are used to analyze the current and voltage distribution in the circuit. These two laws are Kirchhoff's current law and Kirchhoff's voltage law respectively.
Kirchhoff's Law of Current: In any circuit, the sum of currents entering any node (connection point) is equal to the sum of currents leaving the node. The mathematical expression is: σ iin = σ iout, where σ iin represents the sum of currents flowing into the node and σ iout represents the sum of currents flowing out of the node.
Kirchhoff's Law of Voltage: In any closed circuit, the sum of voltages is equal to the sum of voltages consumed by voltage sources and resistance elements. The mathematical expression is: σ vsource+σ vresistor = 0, where σ vsource represents the sum of all voltage sources and σ vresistor represents the sum of voltages consumed by all resistance elements.
Application of Kirchhoff's current law
1, node current analysis: Kirchhoff's current law can be used to solve the current distribution of nodes in complex circuits. By dividing nodes into input and output branches, the relationship between currents of each node can be established, thus simplifying circuit analysis.
2. Current calculation: Kirchhoff's current law can be used to calculate the current value in each branch of the circuit. By writing the node equation and applying Kirchhoff's current law to solve the equation, the current value in each branch can be determined.
3. Layout and connection of components: In circuit design, Kirchhoff current law can be used to determine the layout and connection of components. By analyzing the current relationship of each node in the circuit, appropriate component parameters and connection modes can be selected to meet the requirements of circuit design.