If you’ve always wondered how hearing aids were made, then check out this “How it’s Made” segment. Video after the jump.
Also sometimes used was a desk with a built-in amplifier into which a microphone and earphones could be plugged; these worked better than passive ear trumpets but were not portable. Now, however, the most common style is a small electronic device that fits into the wearer’s ear. The first variety of this device had a rectangular battery pack connected by a thin wire, intended to be held in a pocket