Kirchhoff’s Current Law
Kirchhoff’s Current Law states that the algebraic sum of currents at a node is zero a ‘node’ is the technical term for a junction in a circuit, where two or more branches are joined together. b) the phrase ‘algebraic sum’ reminds us that we have to take account of the current direction, as well asmagnitude, when applying Kirchhoff’s Current Law. This Law is used in circuit analysis to define relationships between currents flowing in branches of the circuit. To apply Kirchhoff’s Current Law rigorously, we must first make an arbitrary choice of positive current direction. Suppose currents flowing in to the node (I1, I2) are treated as positive contributions to the algebraic sum (and conversely currents flowing from the node are treated as negative contributions), then the algebraic sIt must be emphasised that the choice of sign convention when using Kirchhoff’s Current Law is entirely arbitrary and, of course, makes no difference to the result obtained. However, it is good practice t...