Analog circuit design

[Muthuraja.M]

Hi friends,

I want to know the reason of why the input impedance is always want to be high, and the output impedance is always be low ?

Please give me valid reasons.

Thanks in advance.

 

[crutschow]

It should be obvious. You want a high input impedance to minimize the voltage error due to the source impedance. You want a low output impedance to minimize the voltage error due to the load impedance. In both case the two impedances are in series and thus will give a voltage drop due to the voltage divider action.