Transistor radio
A transistor radio is a small portable radio receiver that uses transistor-based circuitry. Following their development in 1954, made possible by the invention of the transistor in 1947, they became the most popular electronic communication device in history, with billions manufactured during the 1960s and 1970s. Their pocket size sparked a change in popular music listening habits, allowing people to listen to music anywhere they went. Beginning in the 1980s, however, cheap AM transistor radios were superseded by devices with higher audio quality such as portable CD players, personal audio players, boomboxes, and (eventually) smartphones, some of which contain radios themselves.
TR-55
Akio Morita and Masaru Ibuka, then operating under the business name Tokyo Tsushin Kogyo, had been working on plans to introduce a transistor radio to the market since 1953. When the TR-55 was released in Japan in August 1955, it was the first transistor radio marketed in that country. The TR-55 featured the Sony name, but the company did not officially change its name to Sony until January 1958.