"This black t-shirt, which says “Silence = Death” with a pink triangle, symbolizes the struggle against AIDS.
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This Sony "Walkman" portable tape player dates from the early 1980s. Originally introduced in 1979 as the “Soundabout,” two people could listen simultaneously while a small microphone permitted them to converse without removing their headsets. Powered by a 9-volt battery, the recorder sold we
Before 1954, so-called portable radio receivers used vacuum tubes to receive and amplify signals. The large batteries needed to power most tubes made radios large and heavy. Receivers built with subminiature tubes existed but were expensive. The invention of transistors in 1947 allowed engineers