How is the gain of a differential amplifier defined?

The gain of a differential amplifier is defined as the ratio of the output voltage to the input voltage. This means it quantifies how much the amplifier increases the voltage level from its input to its output, which is fundamental in various applications, especially in neurophysiologic monitoring where small voltage changes can carry significant information.

In the context of a differential amplifier, this relationship is crucial as it allows for the amplification of the difference between two voltages while rejecting any common noise present on both inputs. Understanding that gain is specifically related to voltage helps in designing and interpreting the performance of amplifiers in clinical settings.

The focus on voltage rather than current, power, or frequency is significant as it emphasizes the fundamental operation of how differential amplifiers are utilized in medical devices, particularly in monitoring systems where precise voltage measurements are pivotal.