Hearing aids are basically microphones that convert sound into electrical signals. It makes some sounds louder so that a person with hearing loss can listen, communicate, and participate more fully in daily activities. A typical hearing aid has three basic parts: a microphone, amplifier, and speaker. The hearing aid receives sound through a microphone, which converts the sound waves to electrical signals and sends them to an amplifier. The amplifier increases the power of the signals and then sends them to the ear through a speaker.