non inverting amplifier problem

[charliehardy]

why an non inverting amplifier has a so high input impedance compared to the out put impedance

 

[Prototyp_V1.0]

Because it's input is connected directly to the opamp's noninverting input wich have very high input impedance. That's why.

 

[charliehardy]

hey thanks man

 

[LvW]

Because it's input is connected directly to the opamp's noninverting input wich have very high input impedance. That's why.

That`s only one of two reasons.
The most important and most interesting influence comes from the feedback action.
The effective input resistance of the non-inverting circuit equals the opamps input resistance multiplied with the loop gain (which may be rather large in some cases).
Example: A unity gain amplifier has a loop gain equal to the open-loop gain of the opamp (1E4...1E5).

 

[adnansarwar2050]

if there is no high impedance then applied signal which is required to be amplified will be grounded through other grounded pin.