What kind of aids did hearing aids featuring transistor technology primarily become?

Hearing aids featuring transistor technology primarily evolved into in-the-ear devices due to the miniaturization and efficiency improvements that transistors provided. With the advent of transistor technology, hearing aids could be made smaller and more compact, allowing them to fit into the ear canal rather than only being worn behind the ear or as larger external devices. This made them more discreet and comfortable for users, as they are less visible and offer a more natural acoustic experience since they can be positioned closer to the eardrum.

Transistor technology allowed for advancements in sound processing, making in-the-ear devices capable of more sophisticated functions like noise reduction and feedback suppression that improved overall hearing experience. Thus, the combination of size reduction and improved performance characteristics made in-the-ear devices a significant development in hearing aid technology during that period.