Seventy years ago this month, this electronics hobbyist is undoubtedly the first on her block to own a transistor radio of her own construction. She is showing off three coveted CK722 transistors, complete with red dots. They had been developed by Bell Labs only five years earlier, and they were still costly devices. But the venerable CK722 was “only” $7.60 each ($87.39 in 2023 dollars).  As such the well-heeled experimenter could start using them in simple circuits.

The October 1953 issue of Popular Mechanics shows two radio receivers using the new transistor. The one-transistor set is within the grasp of the beginner. And for the advanced student, the three transistor set could drive a loudspeaker. It was assumed that the expensive devices would be re-used in other circuits, so they plugged in to transistor sockets. The magazine noted the importance of marking the sockets so that the transistor was plugged in correctly. It warned that before turning on the power, to check the polarity, and then check it again. Turning it on with the wrong polarity would prove costly, since the transistor junctions would be destroyed immediately.