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Topic: Hard amplifier problem - Pleease anwer (Read 3 times) previous topic - next topic

anb2020


Did you simulate it?  (my link above, CircuitLab)

Yes, Vout=Vin.  Value of resistor doesn't matter. You can even put 0R.



Yes I did ..
But the graph didn't make sense ..
Maybe I made a mistake .. I dunno ..

But are you sure .. If the op-amp is idea , Vin=Vout .. Even with the positive feedback!

vasquo



Grumpy_Mike

Yes but as I mentioned before the input impedance is high and the output impedance is low therefore there is a current gain even if there is no voltage gain.

vasquo

Quote
there is a current gain even if there is no voltage gain.


An opamp by definition is a voltage amplifying device, not a current amplifying device.

Don't confuse more output current drive capability with current gain.

In fact, current output capability of any opamp can be further increased by strapping on discrete NPN/PNP booster circuit at it's output... but it's still a voltage amplifier.

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