Why zero output impedance in an ideal op-amp?

Why zero output impedance in an ideal op-amp?

• A. To minimize current drawn from the supply
• B. To increase the gain beyond its limit
• C. To require larger external components
• D. To preserve signal integrity when delivering power

Answer: (D)

The main idea here is that an ideal op-amp behaves like a perfect voltage source at its output. With zero output impedance, the output voltage stays fixed regardless of how much current the load draws (as long as you stay within the supply limits). This means when you deliver power to a load, the voltage seen by the load doesn’t sag or distort as the load current changes. In other words, the signal is preserved in amplitude and shape because the source doesn’t drop voltage under load or during transients. That’s why preserving signal integrity when delivering power is the best explanation. The other options don’t address how the output behaves under load: output impedance doesn’t set supply current, doesn’t by itself raise gain, and doesn’t require larger external components.

The main idea here is that an ideal op-amp behaves like a perfect voltage source at its output. With zero output impedance, the output voltage stays fixed regardless of how much current the load draws (as long as you stay within the supply limits). This means when you deliver power to a load, the voltage seen by the load doesn’t sag or distort as the load current changes. In other words, the signal is preserved in amplitude and shape because the source doesn’t drop voltage under load or during transients.

That’s why preserving signal integrity when delivering power is the best explanation. The other options don’t address how the output behaves under load: output impedance doesn’t set supply current, doesn’t by itself raise gain, and doesn’t require larger external components.