In an open-loop configuration, op-amps are what?

In an open-loop configuration, op-amps are what?

• A. Stable to large changes
• B. Independent of power supply
• C. Immune to noise
• D. Sensitive to small input voltage variations

Answer: (D)

Open-loop means no feedback, so the output equals the open-loop gain times the difference between the inputs. That gain is extremely large, often 100,000 to 1,000,000, so even a tiny input voltage difference—on the order of microvolts—drives the output all the way to one of the supply rails. Because of that, open-loop op-amps are essentially highly sensitive detectors: any small variation at the inputs, including noise or offset voltage, pushes the output to saturation. This is why they’re not used for linear amplification but rather as comparators or in saturation by design. The other statements don’t fit: the device wouldn’t stay stable for large changes without feedback; performance depends on the supply rails; and noise or offsets are amplified, not ignored.

Open-loop means no feedback, so the output equals the open-loop gain times the difference between the inputs. That gain is extremely large, often 100,000 to 1,000,000, so even a tiny input voltage difference—on the order of microvolts—drives the output all the way to one of the supply rails. Because of that, open-loop op-amps are essentially highly sensitive detectors: any small variation at the inputs, including noise or offset voltage, pushes the output to saturation. This is why they’re not used for linear amplification but rather as comparators or in saturation by design. The other statements don’t fit: the device wouldn’t stay stable for large changes without feedback; performance depends on the supply rails; and noise or offsets are amplified, not ignored.