Operational amplifiers — functional block naming: the op-amp configuration in which the output voltage equals the algebraic difference between two input voltages (with appropriate gain scaling) is called a(n) ______. Provide the standard name used in analog circuit design.

Introduction / Context:
An essential building block in analog electronics is the stage that produces an output proportional to the difference between two input voltages. This function underlies sensor bridge readouts, audio balancing, and noise-rejecting measurements, and it is foundational to instrumentation amplifiers and operational amplifier (op-amp) applications. The question asks for the standard name of the op-amp circuit that delivers V_out proportional to (V_in+ − V_in−).

Given Data / Assumptions:

• Two input voltages are applied at separate inputs.
• The desired output is proportional to their difference, possibly scaled by a gain.
• We assume linear operation of an op-amp-based topology.

Concept / Approach:
The circuit that outputs a scaled difference of two input nodes is called a differential amplifier. In its classic four-resistor form, V_out = (R2/R1) * (V2 − V1) when resistor ratios are chosen appropriately. This topology rejects any voltage common to both inputs (common-mode), a key feature for noise suppression in practical systems where both leads pick up interference.

Step-by-Step Solution:

Verification / Alternative check:
Examine integrator and differentiator: they implement calculus operations on a single input, not subtraction of two inputs. Voltage regulators maintain constant output independent of load; they are not subtraction stages. Therefore only the differential amplifier matches the stated behavior.

Why Other Options Are Wrong:

• Integrator: outputs time integral of a single input; not a two-input subtraction.
• Differentiator: outputs time derivative; again, not a difference between two inputs.
• Voltage regulator: maintains constant output; not a differential stage.
• Instrumentation preamplifier: related but is a multi-op-amp architecture built from differential stages; the base name remains differential amplifier.

Common Pitfalls:
Confusing “differential amplifier” with “difference amplifier” versus “instrumentation amplifier.” The difference amplifier is the canonical four-resistor instantiation; an instrumentation amplifier adds input buffers and programmable gain while preserving differential behavior.

Final Answer:
Differential amplifier