What type of amplifiers are utilized for recording biological signals in EEG instruments?

Differential amplifiers are utilized for recording biological signals in EEG instruments because they are specifically designed to amplify the difference between two input signals while rejecting any common noise or interference present in both signals. This feature is crucial in EEG applications, as the electrical activity of the brain (the signals of interest) is often mixed with various forms of electrical noise, including artifacts from muscular activity and electromagnetic interference.

By using differentially amplified signals, EEG instruments can improve the clarity and accuracy of the recorded brain waves. The differential nature of these amplifiers helps ensure that the resulting output is more representative of the true electrical activity of the brain rather than being distorted by external noise factors. This enables the effective monitoring and analysis of brain function, making differential amplifiers the standard choice in EEG recordings.

Operational amplifiers, while they can be used as components within differential amplifiers, are more general purpose and may not provide the same noise rejection needed for the precise measurements required in EEG. Inverting and summing amplifiers serve different functions in signal processing and are not specifically tailored for biological signal recording in the same way that differential amplifiers are.