The opamp circuit is simple ... Technically, devices like this are not really hearing aids, they are “personal sound amplifiers” and the FDA warns people not to substitute them for hearing ...

Epson has unveiled its latest power management IC, the S1A00210B, designed for hearing aids and other compact electronic devices.

At its most simplistic, a hearing aid should just be a battery, microphone, amplifier, and speaker ... How about the circuit: a pure analog solution, or a digital solution that incorporates ...