Hearing aids have been around for centuries. But it’s only been in the last half-century that they’ve become small and powerful enough to become a not so burdensome part of everyday life.

This is in large part thanks to the advance of two strands of modern technology. First, the development of the transistor starting in the 1950s. Then, the explosion of digital technology that took off in the 1990s. These two areas of technological advancement are the foundation of the modern, powerful, and visually subtle hearing aid.

It’s hard to compare today’s hearing aids to those of earlier centuries. The hearing “trumpets” of yore were basically musical instruments in reverse, large funnels that concentrated sounds from a wider area into a small opening that fit into the ear. “Organic” amplification with no boost from electricity, they needed to be big — and yes, some of them were the size of a trumpet.

Later, around the turn of the 20th century, electricity and other technologies were adapted to help the hard of hearing. But there wasn’t anything subtle about these early “modern” devices either. They were boxes — sometimes held up by neck straps — that housed copper wiring and old-school vacuum tubes (and let’s not forget the substantial batteries that powered them). If nothing else, these hearing aids provided users with a good workout.

But the transistor and then the computer chip have — thankfully for the backs of hard of hearing — created the small, lightweight modern hearing aid. Today, tucked subtly behind — or even in — the ear, they are computers with the processing power that, not so long ago, required machines the size of suitcases.