Who invented the first portable radio? What were they used for? - Quora
1947 – The Invention of the Transistor | Philip Harris
The Transistor Radio | Nuts & Volts Magazine
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Regency Model TR-1 Transistor Radio | National Museum of American History
File:Vintage Continental Transistor Radio, Model TR-660, AM Band, 6 Transistors, Continental Merchandise Company, Made In Okinawa (Japan), Circa 1963 (45365151335).jpg - Wikimedia Commons
Regency Model TR-1 Transistor Radio | National Museum of American History