Which statement best describes an isolation amplifier's effect on noise and grounding issues in a measurement system?

Which statement best describes an isolation amplifier's effect on noise and grounding issues in a measurement system?

• A. It increases noise immunity by amplifying noise.
• B. It ties the input and output grounds together for better stability.
• C. It electrically isolates input from output while preserving signal amplitude, reducing ground loops and noise.
• D. It only changes signal frequency.

Answer: (C)

Isolation amplifiers provide galvanic isolation between input and output, which breaks ground loops and reduces noise while keeping the signal amplitude intact. In many measurement setups, different pieces of equipment sit at different ground potentials. If those grounds are tied together, small ground currents can flow and inject noise into the signal. An isolation amplifier floats the measurement side with its own ground reference, so noise and hum on the system ground aren’t carried into the signal path. At the same time, it transmits the signal without significant attenuation, preserving amplitude (and typically bandwidth) so the measurement remains accurate. This combination—separating the grounds to avoid ground-loop noise while maintaining the signal level—is what makes isolation amplifiers effective. The other ideas don’t fit because tying input and output grounds defeats isolation and reintroduces ground-loop noise, and simply changing the signal frequency isn’t the purpose of an isolation amplifier. The primary function is to isolate while preserving the signal, not to alter frequency content or to amplify noise.

Isolation amplifiers provide galvanic isolation between input and output, which breaks ground loops and reduces noise while keeping the signal amplitude intact. In many measurement setups, different pieces of equipment sit at different ground potentials. If those grounds are tied together, small ground currents can flow and inject noise into the signal. An isolation amplifier floats the measurement side with its own ground reference, so noise and hum on the system ground aren’t carried into the signal path. At the same time, it transmits the signal without significant attenuation, preserving amplitude (and typically bandwidth) so the measurement remains accurate. This combination—separating the grounds to avoid ground-loop noise while maintaining the signal level—is what makes isolation amplifiers effective.

The other ideas don’t fit because tying input and output grounds defeats isolation and reintroduces ground-loop noise, and simply changing the signal frequency isn’t the purpose of an isolation amplifier. The primary function is to isolate while preserving the signal, not to alter frequency content or to amplify noise.