The nervous system is one of the most important systems in the human body and its health is crucial for the normal functioning of the human body. In examining the functionality of the nervous system, as well as the most common and best method of discovering epilepsy, electroencephalograph (EEG) is used, which measures the voltage of the brain by means of electrodes that are placed on the patient's head. The result of tests using EEG is called electroencephalogram whose function is to record brain waves. Electroencephalogram may be disrupted due to various disturbances. To minimize or alleviate the impact of interference, the different amplifiers that are connected in cascade are used. A block scheme of the amplifier consists of the parts that signal needs to go through in order to eliminate all interference and to enhance the signal required for the formation of the results. Parts of the block scheme of the amplifier are: RFI filter, instrumentation amplifier, high-pass filter, non-inverting amplifier, low pass filter, a programmable amplifier, followed by an analog-to-digital conversion, resulting in the emergence of the digital signal.