Ideal op-amp

Ideal op-amp:  

An ideal op-amp would exhibit the following electrical characteristics: 

Infinite voltage gain 

Infinite input resistance so that almost any signal source can drive it and there is no loading on the preceding stage. 

Zero output resistance Ro so that output can drive an infinite number of other devices. 

Zero output voltage when input voltage is zero. 

Infinite bandwidth so that any frequency signal from 0 to ∞Hz can be amplified without attenuation. 

Infinite common mode rejection ratio so that the output common-mode noise voltage is zero. 

Infinite slew rate so that output voltage changes occur simultaneously with input voltage changes.