# Op Amp Impedance Matching

A $$\SI{1}{\volt}$$ DC voltage source with an internal resistance of $$\SI{10}{\ohm}$$ is used to drive a $$\SI{1}{\ohm}$$ load. Because of the source-load impedance mismatch (10 to 1), the circuit has relatively poor power transfer to the load.

To increase the load power, a more elaborate circuit is constructed, as shown below.

The operational amplifier (op amp) used in this circuit is ideal, which means that it has the following properties:

• the voltages at the ($$+$$) and ($$-$$) terminals are identical;
• the currents into/out of the ($$+$$) and ($$-$$) terminals are zero.

The op amp has its own $$\SI{5}{\volt}$$ DC power supply.

What is the ratio of the load power in the second circuit to the load power in the first circuit?

As a bonus, what would be an appropriate name for this op amp configuration?


Note: The curved line coming out of $$V_{DC-}$$ indicates that an electrical connection is not made there with the feedback line.

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