# Maximum Power Transfer Theorem DC & AC

Thread Starter

#### Agonche

Joined Aug 26, 2011
30
Can anyone help me with the theorem "Maximum Power Transfer" on DC and AC circuits.

I know that
$$R_{L}=R_{S}$$
and
$$X_{L}=-X_{S}$$

but why. I need a proof.
can anyone explain the derivative of dP/dR, or how it should be solved.
any information would be appreciated.

#### jegues

Joined Sep 13, 2010
733
Can anyone help me with the theorem "Maximum Power Transfer" on DC and AC circuits.

I know that
$$R_{L}=R_{S}$$
and
$$X_{L}=-X_{S}$$

but why. I need a proof.
can anyone explain the derivative of dP/dR, or how it should be solved.
any information would be appreciated.
If you follow this link,

http://en.wikipedia.org/wiki/Maximum_power_transfer_theorem

Instead of solving for dP/dR, they simply solve for the when the denominator in the P(R) expression is minimized. (This gives the maximum P(R))

The same approach is applied for AC circuits, only holding RL at a fixed value.

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