The Differential Amplifier

In Chapter 1, we referred to the amplifier as the heart of the EEG machine. This chapter returns to the topic to fill in some important details. We begin with a consideration of electronic amplifiers in general, and then continue with a discussion and analysis of the differential amplifier. As we will see, the differential amplifier is a specially designed device for recording bioelectric activity, and it is employed universally in EEG machines. Our objective in this chapter is to find out precisely what this amplifier does and how it accomplishes its purpose.