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History of Hearing Aid. 한림대학교 자연과학대학 언어청각학부 이 경 원 Source from Danasound. History of Hearing Aids. In the beginning … 18th, 19th Century Ear Trumpets Amplified sound by 5 to 40dB Easy to fit Low maintenance Bulky and Visible. Vacuum Tube Amplifiers. Early 1900s through 1930s
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History of Hearing Aid 한림대학교 자연과학대학 언어청각학부 이 경 원 Source from Danasound
History of Hearing Aids • In the beginning… • 18th, 19th Century Ear Trumpets • Amplified sound by 5 to 40dB • Easy to fit • Low maintenance • Bulky and Visible
Vacuum Tube Amplifiers • Early 1900s through 1930s • Vacuum Tube powered Body Aids • Bulky and expensive • Carbon Microphone • 2 Batteries required • True portableamplification
Transistor Amplifiers & Miniaturization • Transistor Models - 1950s • Smaller, more portable • Lighter, fewer batteries
Eyeglass Models • 1950s through 1960s • Continued miniaturization • Decreased visibility
Micro-Miniature Hybrid Circuits • BTEs - Integrated Circuits - 1960s • ITEs - Miniature IC’s - 1970s • Analog Programmables - 1980s • CIC - Ultraminiature multi-chip Hybrid Circuits - 1990s • Digital Programmables - 1990s