What is the function of an isolation amplifier?

• A. To amplify the signal.
• B. To provide impedance matching without isolation.
• C. To electrically isolate input from output while preserving signal amplitude.
• D. To convert digital signals to analog.

Answer: (C)

The function of an isolation amplifier is to create galvanic isolation between the input side and the output side while passing the signal with its amplitude preserved. This isolation barrier prevents electrical faults, ground loops, or high common-mode voltages on the sensor side from being transmitted to the processing side, protecting equipment and operators and reducing noise. The signal is transferred across the barrier without a direct electrical connection, typically using optical, transformer, or capacitive coupling, so the measured amplitude remains the same (within the device’s specified accuracy and bandwidth). While some isolation amplifiers may provide gain, the primary purpose is to isolate, not to amplify or to match impedance without isolation. They are not about converting digital to analog; their key role is preserving signal integrity while keeping the two sides electrically separate.