I'm a few days behind on this. On October 18 Bob Crane pointed out that Garrison Keillor marked the anniversary of the broadcast band "transistor radio." I had mine (a 1970s version), and it did indeed allow me to listen to that seditious rock music without parental interference. Looking around the shack, I still have items in use that have "Transistorized" as part of their product name (like my Lafayette Radio Electronics Transistorized DC Power Supply."
Garrison (on October 18, 2017):
Transistors were a big breakthrough in electronics — a new way to amplify signals. They replaced vacuum tubes, which were fragile, slow to warm up, and unreliable. During World War II, there was a big funding push to try to update vacuum tubes, since they were used in radio-controlled bombs but didn't work very well. A team of scientists at Bell Laboratories invented the first transistor technology in 1947. But the announcement didn't make much of an impact because transistors had limited use for everyday consumers — they were used mainly in military technology, telephone switching equipment, and hearing aids.
Several companies bought licenses from Bell, including Texas Instruments, who was bent on being the first to market with a transistor radio. Radios were mostly big, bulky devices that stayed in one place — usually in the living room — while the whole family gathered around to listen to programming. There were some portable radios made with vacuum tubes, but they were about the size of lunch boxes, they used heavy nonrechargeable batteries, they took a long time to start working while the tubes warmed up, and they were fragile. Texas Instruments was determined to create a radio that was small and portable, and to get it out for the Christmas shopping season. They produced the transistors, and they partnered with the Regency Division of Industrial Development Engineering Associates, who manufactured the actual radios. Their new radio, the Regency TR-1, turned on immediately, weighed half a pound, and could fit in your pocket. It cost $49.95, and more than 100,000 were sold.
Texas Instruments went on to pursue other projects, but a Japanese company called Tokyo Tsushin Kogyo decided to make transistor radios their main enterprise. They were concerned that their name was too difficult for an American audience to pronounce, so they decided to rebrand themselves with something simpler. They looked up the Latin word for sound, which was sonus. And they liked the term sonny boys — English slang that was used in Japan for exceptionally bright, promising boys. And so the company Sony was born. Soon transistor radios were cheap and prevalent.
With transistor radios, teenagers were able to listen to music out of their parents' earshot. This made possible the explosion of a new genre of American music: rock and roll.