The transistor radio (or transistor) is a small radio receiver.

RCA demonstrated a prototype transistor radio in 1952. The first commercial transistor radio, the Regency TR-1, was announced on October 18, 1954, and put on sale at Christmas 1954. It cost $49.95 (the equivalent of $334 in year-2003 dollars).

Originally introduced by Texas Instruments as a demonstration of the transistor, TI lost interest, leaving the transistor radio to be popularized by Sony.

The use of transistors instead of vacuum tubes as the amplifier elements meant that the device was much smaller and required far less power to operate than a tubed radio. The typical portable radio of the fifties was about the size and weight of a small laptop computer, and contained several heavy (and non-rechargeable) batteries : one or more A batteries to heat the tube filaments and a large 45 to 90 volt B battery for plate voltage. By comparison, the "transistor" was about the size and weight of today's cassette-playing Walkman and operated off a single compact 9 V battery. (The now-familiar 9 V battery was introduced specifically for powering transistor radios).

Transistor radios did not become popular until the early sixties, when costs came down. Although usually equipped with headphone jacks, the most common way listeners used them was by holding the entire radio directly against the side of the head, with the speaker against the ear. These radios, like the tube-based portable radios of the day, were monaural, and received only the 540–1600 kilocycle AM broadcast band. Holding the radio to the ear minimized the irritatingly "tinny" sound, commonly attributed to their tiny speakers, but equally due to the use of inadequate coupling capacitors.

The transistor radio remains the single most popular communications device in existence. Some estimates suggest that there are at least seven billion of them in existence, almost all tunable to the common AM band, and an increasingly high percentage of those also tunable to the FM band. Some receive shortwave broadcasts as well. Most operate on battery power. They have become small and cheap due to improved electronics which pack millions of transistors on one integrated circuit or chip. The prefix "transistor" basically now means an old pocket radio; it can be used to refer to any cheap radio but the term itself is somewht obsolescent these days, since virtually all commercial broadcast receivers, pocket-sized or not, are transistor-based.

See also: broadcasting

Further links

• TI Information Bulletin First Commercial Transistor Radio October 18, 1954
• About the Regency transistor radio
• Michael F. Wolff: "The secret six-month project. Why Texas Instruments decided to put the first transistor radio on the market by Christmas 1954 and how it was accomplished." IEEE Spectrum, December 1985, pages 64-69