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5.6.1 Kirchhoff’s Laws Jonathan Li ( ? post_type=module&byline_id=895) t Uncategorized r o p Moving on to larger complex circuits, simple use of Ohm’s law is not sufficient p u for circuit ysis. Assuming connecting wires are perfect conductors (i.e. zero S ) Kirchhoff’s laws can be applied to find the currents and voltages of different paths in the circuit. The most fundamental concepts of Electrical engineering are the two laws, Kirchhoff’s current law (KCL) and Kirchhoff’s voltage law (KVL), discovered by a German physicist named Gustav Robert Kirchhoff. A few definitions you should know before moving on to Kirchhoff’s laws. A node is a point of connection between two or more circui ements. ( ) A loop is a closed path through a circuit where no node is encountered more than once. ( ) Kirchhoff’s Current Law Kirchhoff’s Current Law (KCL) is a direct consequence of the law of conservation of charge – the pr iple tha ectric charge cannot be created or destroyed. The physical (intuitive) implication of KCL is that: the sum of currents (electrical charges) entering a node equals the sum of currents (electrical charges) leaving a node ∑iin = ∑iout This can be stated equivalently, and more conveniently to remember for calculations, that: the mathematical sum of currents leaving a node is zero m ∑ in = 0 n=1 In the first equation, currents that enter the node should be summed tly of current i