Developed in 1947 but commercialized in 1954, transistor radios are small. Battery-operated portable radios that fit in a pocket. They rely on transistors rather than vacuum tubes.
There were several attempts to build radios with transistors but none were optimal until 1954. Eventually, a Texas Instruments team invented the Regency TR-1, the first radio miniaturized with transistors.
The TR-1 was a hit. No sooner did the public start buying the expensive (the TR-1 cost $50, $465 in 2018 dollars) than copycats sprang up. Subsequently, within a decade, $10 Asian transistor radios were common.
Transistor radio sales number in the billions. Until smartphones, the transistor radio was the most popular electronic ever sold.
The transistor radio was a massively popular consumer product. Significantly, the radio proved the mass-market for miniaturized products based on transistors.