Question

An ideal operational amplifier has:

• A. Infinite input impedance and zero output impedance
• B. Zero input impedance and infinite output impedance
• C. Infinite gain and infinite output impedance
• D. Finite gain and finite bandwidth

Hint:

Always remember: Ideal op-amp assumptions include infinite gain, infinite input impedance, zero output impedance, and infinite bandwidth.

Answer 1

The Correct Option is A

An ideal operational amplifier, or op-amp, is a fundamental component in the field of electronics and signal processing. To determine its key characteristics, we analyze the given options:

1. Option 1: Infinite input impedance and zero output impedance
   This is the correct answer. An ideal op-amp should have an infinite input impedance to ensure that it does not load the source driving it and draws no current. A zero output impedance is desired so that it can deliver maximum power to the load connected to it without loss.
2. Option 2: Zero input impedance and infinite output impedance
   This is incorrect, as zero input impedance would mean that the op-amp would load the input signal heavily, which is not desirable. Additionally, infinite output impedance is not suitable, as it would prevent power delivery to the load.
3. Option 3: Infinite gain and infinite output impedance
   This is partially correct, as an ideal op-amp is assumed to have infinite gain, meaning it can amplify any input voltage difference infinitely. However, infinite output impedance is incorrect as discussed earlier.
4. Option 4: Finite gain and finite bandwidth
   This is incorrect for an ideal op-amp. While real-world op-amps have finite gain and bandwidth, an ideal op-amp is characterized by infinite gain and unlimited bandwidth.

In conclusion, the correct properties of an ideal operational amplifier are "Infinite input impedance and zero output impedance." This ensures optimal performance in practically all circuit applications, emphasizing minimal input loading and maximal output power transfer.