Tellegens Theorem

Tellegen theorem states that the summation of instantaneous powers for the n number of branches in an electrical network is zero.

Suppose n number of branches in an electrical network have i₁, i₂, i₃, .............i_n 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, ........... v_n respectively. If these voltages across these elements satisfy Kirchhoff Voltage Law then,