The amplifier is another necessary element of a hearing aid: this component makes it possible to increase the sound perceived by the microphone which is then projected through the earpiece. In this process, the amplifier increases the range of action of the sound. But not all sounds are increased indiscriminately: in fact the amplifier, also called microprocessor, based on appropriate adjustments, processes only certain sounds and, subsequently, projects them to the eardrum. The hearing aid is a small PC, which enhances some sounds and eliminates others, as is the case of background noise.