Hearing aids are small amplifiers that amplify sounds that are otherwise inaudible, and then utilize the residual hearing of the hearing impaired, so that the sound can be sent to the auditory center of the brain, and the sound can be felt. It is a great convenience for the hearing impaired.
Hearing aids are mainly composed of microphone, amplifier, headphones, power supply and volume control. Hearing aids are divided into air-conducted hearing aids and bone-conducted hearing aids according to the way of conduction; classified by the way of use as box-type, spectacle-type, hairpin-type, back-of-the-ear-type, in-the-ear-type, ear canal-type, and deep-ear canal-type hearing aids.
Since the beginning of the twentieth century, electronic hearing aids have been activated, the structure of the hearing aid has not changed much, and is still composed of microphone, amplifier, receiver and power supply. However, the size of each part of the hearing aid has gradually decreased, and the sound quality has improved with more selective control.
Hearing aids are instruments that help improve hearing, and are actually a small semiconductor loudspeaker that amplifies weak sounds and transmits them to the earphones, so that the parts of the body that have lost hearing can hear with the help of amplification.
The best way to choose a hearing aid is to go to the hospital, do a comprehensive examination of the hearing, with electrical audiometry and other instruments to accurately evaluate the degree of deafness, and then choose a hearing aid, if there is no corresponding local conditions of the hospital, the degree of hearing loss and the power of hearing aids can be selected according to the oral test to estimate. For example, people who can not hear the whispering sound of hearing loss of 30 to 40 dB, can not hear the whispering sound of hearing loss of about 40 to 50 dB, it is appropriate to purchase low-power and medium-power hearing aids; can not hear the ordinary speech of hearing loss of about 50 to 60 dB, can not hear the loud speech of hearing loss of 60 to 70 dB, can be equipped with medium-power and high-power type hearing aids; can not hear the loud shouting sound of hearing loss of 70 to 80 dB, can be equipped with medium-power and high-power type hearing aids; can not hear loud shouting sound of hearing loss of 70 to 80 dB. Hearing loss of 70 to 80 decibels, the choice of medium and high power hearing aids; full force shouting can not hear the hearing loss of about 80 to 90 decibels or higher, can be equipped with high power and extra high power hearing aids.