DC Network Theorems Unit 2 – Kirchhoff's Current Law
The connection on each side of the power source is represented by a node (NODE 1 and
NODE 2).
Kirchhoff's current law can be stated in two ways:
- The sum of the currents leaving a node in a circuit equals the sum of the currents entering the
node. - The algebraic sum of the currents at any node in a circuit must equal zero.
If your calculations show a net gain or loss of node current, you have made an error.
When applying an algebraic equation to node current, you must give a + or - sign to the current.
In dealing with current flow, consider currents flowing into a node as negative (-), such as I 1
and I 2 into NODE 2. Consider currents leaving a node as positive (+), such as IT out of NODE 2.