Transistor radio

From Exampleproblems

A transistor radio is a small transistor-based 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 by the Regency Division of Industrial Development Engineering Associates of Indianapolis, Indiana and put on sale in November of 1954. It cost $49.95 (the equivalent of $361 in year-2005 dollars) and sold approximately 100,000 units.

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 earphone 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^[1] 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 available earphones of the day were single earphones that inserted into one ear. They generally used piezoelectric crystals, a cheap technology that lessened the already-low fidelity of the AM broadcasts they reproduced. They were not ergonomically designed and were uncomfortable. The listening experience was telephone-like. Nevertheless, teenagers, with an earphone plugged into one ear, immersed in a private musical world, became a familiar sight, and one that made Ray Bradbury's description of "seashell radios" in his 1953 Fahrenheit 451 seem prescient. To consumers familiar with the earphone listening experience of the transistor radio, the first Sony Walkman cassette player, with a pair of high-fidelity stereo earphones, would come as a revelation.

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 somewhat obsolescent these days, since virtually all commercial broadcast receivers, pocket-sized or not, are transistor-based.

See also: broadcasting

Notes

• ^  Kilocycles is an old term for what is today known as kilohertz. The hertz was adopted as the new unit of frequency in 1960 (replacing the cycle per second), and became common use in the 1970s.

Further links

• Great pictures and info on vintage transistor radios. Also crystal radios and related radio items. Monthly featured transistor Radio of the Month.

• TI Information Bulletin First Commercial Transistor Radio October 18, 1954

• Website about the first transistor radio by Dr. Steven Reyer, a Professor in the Electrical Engineering and Computer Science Department at the Milwaukee School of Engineering.

• ChildhoodRadios.com Website with restoration resources and community message board operated by Ron Mansfield

• Sarah's Transistor Radios Extensive website displaying over 1500 transistor radios and other information.

Reading

• The Regency TR-1 Family, Sony Transistor Radios, Vintage Micro Transistor Radios, American Shirt-Pocket Transistor Radios and more at EricWrobbel.com
• 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
• Transistor Radios: 1954-1968 (Schiffer Book for Collectors) by Norman R. Smith
• Made in Japan: Transistor Radios of the 1950s and 1960s by Handy, Erbe, Blackham, Antonier (1993) (ISBN 081180271X)
• The Portable Radio in American Life by University of Arizona Professor Michael Brian Schiffer, Ph.D. (The University of Arizona Press, 1991).
• Restoring Pocket Radios (DVD) by Ron Mansfield and Eric Wrobbel. (ChildhoodRadios.com, 2002).
• Sarah's Transistor Radios (Website) by Sarah Lowrey at www.transistor.orgda:Transistorradio

de:Transistorradio ja:トランジスタラジオ nds:Transistorradio