Selecting an amplifier for low-level signals in high-voltage environments: Which amplifier provides high sensitivity to small inputs while protecting the measurement chain from associated high-voltage circuits through galvanic isolation?

Introduction / Context:
Some applications require the measurement of very small signals in the presence of hazardous or noisy high-voltage systems. The measurement chain must be protected while preserving accuracy. An isolation amplifier is specifically designed to transfer analog signals across a galvanic isolation barrier, providing both safety and performance advantages.

Given Data / Assumptions:

• Environment includes high voltage or large ground potential differences.
• Signal of interest is low-level and must be acquired with precision.
• Safety and regulatory compliance demand isolation between domains.
• Bandwidth and linearity requirements are within the isolation amplifier’s capability.

Concept / Approach:
The isolation amplifier breaks the conductive path between sensor and processor grounds while reproducing the analog signal on the isolated side. It mitigates ground-loop errors, tolerates high common-mode voltages, and withstands surges. By transferring the signal via optical, capacitive, or transformer coupling with modulation/demodulation, it preserves both DC content and AC dynamics within its specified bandwidth.

Step-by-Step Solution:

Verification / Alternative check:
Contrast with a basic instrumentation amplifier. While an INA offers excellent CMRR, it does not inherently provide safety isolation; a fault could still propagate through shared grounds. The isolation amplifier uniquely addresses both precision and safety by breaking the ground path.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming high CMRR equals isolation; overlooking isolation barrier creepage/clearance; failing to consider surge ratings and EMI coupling that can still inject noise across the barrier.

Final Answer:
isolation