Circuit Theory-Tellegen Theorem

Tellegen Theorem

 According toTellegen theorem the summation of instantaneous powers for the n number of branches in an electrical network is zero. Are you confused ? Let's explain. Suppose n number of branches in an electrical network have i1, i2, i3, .............in respective instantaneous currents through them. These currents satisfy Kirchhoff's current law. Again, suppose these branches have instantaneous voltages across them are v1, v2, v3, ........... vn respectively. If these voltages across these elements satisfy Kirchhoff Voltage law then,

Where vk is the instantaneous voltage across the kth branch and ik is the instantaneous current flowing through this branch. Tellegen theorem is applicable mainly general class of lumped networks consists of linear, non-linear, active, passive, time variant and time variant elements. This theorem can easily be explained by the following example.

In the network shown, arbitrary reference directions have been selected for all of the branch currents, and the corresponding branch voltages have been indicated, with positive reference direction at the tail of the current arrow. For this network, we will assume a set of branch voltages satisfy the Kirchhoff voltage law and a set of branch current satisfy Kirchhoff current law at each node. We will then show that these arbitrary assumed voltage and currents satisfy the equation.

And it is the condition of Tellegen theorem