For an op-amp output to swing above and below a 0 V reference (i.e., provide positive and negative output voltages), what supply arrangement is required for the op-amp circuit?

Introduction:
Op-amp output swing is fundamentally limited by its supply rails. Generating signals that cross 0 V (true bipolar swing) requires appropriate supply configuration. This question targets the practical requirement for achieving symmetrical positive and negative output excursions around ground.

Given Data / Assumptions:

• Conventional op-amp (not necessarily rail-to-rail) driving a load referenced to ground.
• Desired output swings both above and below 0 V.
• Moderate load currents; linear operation with feedback.

Concept / Approach:
To produce negative output voltages relative to ground, the op-amp must be powered with a negative rail below 0 V (e.g., −V) and a positive rail above 0 V (e.g., +V). A single-supply configuration (0 to +V) typically requires bias shifting (virtual ground) to keep the signal within 0…+V, not around 0 V. Feedback networks or bandwidth do not by themselves create negative swing; they only shape response within supply limits.

Step-by-Step Solution:

Verification / Alternative check:
Data sheets list output swing vs. supply and load; only with a negative rail does the device produce negative output without level-shifting. Lab tests with single-supply show clipping at 0 V unless a mid-supply reference is used (which shifts “ground” for the signal).

Why Other Options Are Wrong:

• Resistive feedback: Controls gain, not swing polarity.
• Zero offset: Reduces DC error but does not create negative swing.
• Wide bandwidth: A speed metric; unrelated to crossing 0 V.

Common Pitfalls:
Assuming rail-to-rail input/output guarantees negative swing on a single supply; forgetting to reference the load and measurement ground correctly; overlooking output headroom limits near rails.

Final Answer:
A negative and positive supply.