[机械工程概论英语语论文.docVIP

机械工程概论双语 课 题： 助听器 姓 名： 谭伟 学 号： 指 导 教 师： 李怀仙 完 成 日 期： 2012年12月27日 成 绩： Abstract Its easy to take sound for granted, but when you lose it ,due to a serious hearing disorder。How do you do ? thankfully this tiny hearing aid bring back the music Loose of hearing causes a serious handicap, but happily It can be remedied thanks to hearing aid. A hearing aid is an electric device which typically fits in or behind the wearers ear, and is designed to amplify and modulate sound for the wearer. Earlier devices, known as ear trumpets or ear horns,Similar devices include the bone anchored hearing aid, and cochlear implant. 图 1 Invisible hearing aid 1. Introduce about hearing Aid Hearing Aid is a help to Hearing crippled improve Hearing impairment, and further increase the session with others of the communication ability of tools, equipment, equipment and instrument, etc. Hearing AIDS have the power and the power of the two kinds, the latter at present has been abandoned. The former and tube type and transistor type two kinds. Transistor type hearing aid the most clever light, appeared in 1950 after replace valve type and is widely used. In a broad sense that can effectively put the sound to the ear various device can see as hearing AIDS, a narrow sense about hearing aid is a electroacoustic amplifier, through it will put the deaf hear voice ambassador to the original can not hear clearly, cant hear voice, this device is hearing aid. 2. Hearing aid development history In 1878, the United States scientists Bell invented the first carbon type hearing aid. The hearing aid is by carbon microphone, headphones, battery, wire etc have been assembled. In 1890, Austrian scientist Ferdinant Alt preparation out of the first generation tube hearing aid. In 1920, thermionic valve (hot cathode tube) was soon, appear vacuum tube hearing aid. With the developing of the tech