query: When was the transistor radio invented?
passage: 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[1] 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 Beginning in the 1980s, however, cheap AM transistor radios were superseded by devices with higher audio quality such as portable CD players, personal audio players, boomboxes, and (eventually) smartphones,[2] some of which contain radios themselves.[3]
passage: Perdio Radio
Perdio Radio was a British electronics company (later Perdio Electronics Limited) founded by Derek Willmott (born 4 January 1924) and Joyce Willmott in 1955. Former RAF pilot Derek Willmott was a DECCA researcher developing RADAR applications and was already an inventor, with designs for multiple miniaturisation applications in consumer electronics, including designs for portable personal tape players (similar to the later success of Sony's Walkman) and small radios and televisions. The newly available transistors allowed the Willmotts to enter the market with Perdio, producing the PR1 in 1957. A 5 Transistor design meant a highly compact and efficient unit which led on to production of 56 models bearing the Perdio name. Perdio also produced the Portarama Television set currently on display in Londons Science Museum along with a 'Spinny' radio.