The unity gain op-amp circuit seems simple, but what use is the amp if it only provides a copy if the input? Why couldn't we just use a wire to connect the source (input) to its load (output) since its just the same? Vin=Vout?
Confused

 

The unity gain op-amp circuit seems simple, but what use is the amp if it only provides a copy if the input? Why couldn't we just use a wire to connect the source (input) to its load (output) since its just the same? Vin=Vout?
Confused

The input impedance will be high and the ouput impedance low. So there is power gain avalable.

 

It's known as a 'buffer', and it amplifies CURRENT rather than voltage...so if you need to drive something with a low input impedance, which would objectionably load down the circuit which precedes it, you can use a buffer to isolate it from that loading...