Ideal Op-Amp Characteristics Analysis

This solution analyzes the characteristics of an ideal operational amplifier (Op-Amp) to determine which statements are correct.

Characteristic 1: Impedance Properties

An ideal Op-Amp is defined by specific input and output impedance values:

• Input Impedance ($Z_{in}$): Should be infinite ($Z_{in} = \infty$). This ensures no current is drawn from the input signal source.
• Output Impedance ($Z_{out}$): Should be zero ($Z_{out} = 0$). This allows the Op-Amp to deliver its full output voltage to the load without any voltage loss due to internal resistance.

The statement "An infinite output impedance and zero input impedance" incorrectly assigns these values. Therefore, characteristic 1 is incorrect.

Characteristic 2: Voltage Gain

An ideal Op-Amp possesses an extremely high, theoretically infinite, open-loop voltage gain ($A_v = \infty$). This high gain is crucial for its amplifying capabilities in various circuit configurations, especially when using negative feedback.

The statement "The Op-Amp must have an extremely high inherent voltage gain" accurately reflects this ideal characteristic. Therefore, characteristic 2 is correct.

Characteristic 3: Slew Rate

The slew rate ($SR$) represents the maximum rate of change of the Op-Amp's output voltage. For an ideal Op-Amp, the slew rate should be infinite ($SR = \infty$), meaning it can respond instantaneously to any changes in the input signal.

A "Zero slew rate" implies the output cannot change, which contradicts the function of an amplifier. Therefore, characteristic 3 is incorrect.

Conclusion

Based on the analysis, only the second characteristic (extremely high inherent voltage gain) correctly describes an ideal Op-Amp.

Correct Option: 2 only