Tellengen’s Theorem: What is Tellengen’s theorem?
Tellengen’s Theorem
In any arbitrary network, the algebraic sum of the powers in all the branches at any given instant is zero,
that is, the algebraic sum of the power delivered by the same elements in network is equal to the power absorbed by the remaining elements present in the network.
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When the current enters at negative terminal of an element, then that element will deliver the power, otherwise it will absorb the power.

The source can absorb power [Fig. (a)] or can deliver power [Fig. (b)] but the passive elements always
absorb power (since the current enters at positive terminal of the respective element).

where b is the number of branches.
Note:
- Tellengen’s theorem depends only on the voltage and current across the element, but not on the type
of the element. - Tellengen’s theorem expresses the conservation of power or energy in the network.
Problem: Question
For the given circuit, calculate

Solution: From the circuit, we have

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Electrical Circuit Theorems
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