The transistor radio was invented in 1947. It allowed people to carry radios with them.

Old portable radios were marvels of technology from the 1950s to the 1980s - Click Americana

The Transistor Radio Nuts & Volts Magazine

Old portable radios were marvels of technology from the 1950s to the 1980s - Click Americana

Old portable radios were marvels of technology from the 1950s to the 1980s - Click Americana

TR-1 The World's First Transistor Radio – Inside the Collection

Let's Get Small SPARK Museum of Electrical Invention

The Transistor Radio Nuts & Volts Magazine

Let's Get Small SPARK Museum of Electrical Invention

SURFING BOOM Surfing Safari

Transistor radio, Ultimate Pop Culture Wiki

The Transistor Radio Nuts & Volts Magazine

The History Behind the Invention of the First Cell Phone - Interesting Engineering