hearing aid, an electronic device that amplifies sound used by people with impaired hearing. The device consists of a microphone, a battery power supply, an amplifier, and a receiver. The microphone receives sound waves directed toward the person with hearing loss, then converts the sound waves to electrical impulses that are amplified with the aid of the power supply, and the receiver converts the electrical impulses back into sound vibrations. Newer, programmable hearing aids can be customized on the basis of the characteristics of an individual’s hearing loss.
