Certified Polysomnographic Technician (CPSGT) Practice Exam

A differential amplifier is designed to amplify the difference between two input voltages while rejecting any signals that are common to both inputs. This type of operation makes it particularly useful in situations where it is essential to eliminate noise and other unwanted common-mode signals, such as in medical and laboratory settings where precise measurements are necessary.

When a differential amplifier receives two input signals, it computes the difference between them and applies gain to this difference. This allows for a more accurate representation of the signal of interest, enabling better analysis and interpretation of the data being measured. The ability to focus only on the difference is what distinguishes a differential amplifier from other types of amplifiers that might average or sum signals without filtering out common interference.

In contrast, other options do not accurately capture the fundamental operation of a differential amplifier. For instance, averaging two signals or amplifying the sum of two voltages implies an operation that does not prioritize the difference, which is central to the function of a differential amplifier. Processing signals from a single source is also outside the scope of a differential amplifier's functionality, as this device specifically requires two inputs to perform its intended purpose effectively.