Transistorradio

En bærbar radiomodtager eller transportabel radiomodtager er en radiomodtager, som i mange årtier stort set har været synonym med en transistorradio eller blot transistor. En transistorradio er en radiomodtager, som anvender transistorer som forstærkerelementer. En bærbar radiomodtager kan fx være en lommeradio, rejsemodtager eller kuffertradio.

En bærbar radiomodtager får typisk elektrisk energi fra batterier eller akkumulatorer. Mange bærbare radiomodtagere har enten en indbygget netdel eller et elektrisk stik til en ekstern, så de kan få energi fra elnettet (220-230V).

Der regnes for i dag 2005 at være ca. 7 milliarder transistorradioer i verdenen.

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Den første kommercielt tilgængelige transistorradio blev præsenteret 18. oktober 1954 af Regency Division of Industrial Development Engineering Associates (IDEA) of Indianapolis, Indiana.^[2] Den hed Regency TR-1 og blev sat til salg november 1954.^[1]^[3]

Transistorradioen blev oprindeligt introduceret af Texas Instruments (TI) for at demonstrere transistoren.^[1]^[3] TI tabte interessen, og transistorradioen blev populariseret af Totsuko (omdøbes senere til Sony).

Anvendelsen af transistorer (af den bipolare variant) i stedet for elektronrør som forstærkerelement, betød af apparatet var meget mindre og behøvede betydeligt mindre energi end lommeradioer med elektronrør. Den typiske bærbare lommeradio fra 1950'erne var på størrelse og vægt som dagens (2005) bærbare computere og indeholdt adskillige tunge (ikke genopladelige) batterier; en eller flere "A" batterier til rørenes glødestrøm og et stort 45–90 volt "B" batteri til anodespænding. Til sammenligning var lomme transistorradioen på størrelse med en Walkman og blev i starten strømforsynet af et lille 22,5V batteri (fx Regency TR-1) og senere af det kendte 9V batteri som faktisk blev specielt designet til transistorradioen.^[1]

Transistorradioer blev først alment populære i de tidlige 1960'erne, da prisen her faldt meget. Datidens transistorradioer blev normalt kun designet til mellembølgebåndet (ca. 540–1610 kHz) og først senere til kortbølgebåndet (mellem ca. 1.700–30.000 kHz) og FM-båndet (ca. 87,5–104 MHz).

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[1]
Transistor radio mini-history Citat: "...CD [civil defense] marks. These were in the shape of little triangular marks which should appear in all the transistor radios made up to 1963. These marks were meant to show the frequencies for the emergency tuning of the radios in case of nuclear attack from the USSR..."
[2]
Texas Instruments: TI Information Bulletin Citat: "...First Commercial Transistor Radio. TI Supplying Transistors for First "Pocket Size" Radio. DALLAS (October 18, 1954) - TI's part in the production of the first commercial transistorized radio receiver will be announced beginning today in newspapers throughout the country. The "pocket size" radio has four TI transistors. It also uses a TI subminiature output transformer...The receiver is being assembled and marketed by the Regency Division of Industrial Development Engineering Associates, Inc., Indianapolis. It will be available this week to the public through sales outlets in Los Angeles and New York City...TIers can justly be proud of being the first to produce a high-gain transistor at a cost permitting its application to the high-volume commercial market..."
[3]
Website about the first transistor radioby Dr. Steven Reyer, a Professor in the Electrical Engineering and Computer Science Department at the Milwaukee School of Engineering, The Breakthrough Breadboard Feasibility Model: The Development of the First All-Transistor Radio,

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Luk

Great pictures and info on vintage transistor radios. Also crystal radios and related radio items.

[radiohistory-1] [1]
Transistor radio mini-history Citat: "...CD [civil defense] marks. These were in the shape of little triangular marks which should appear in all the transistor radios made up to 1963. These marks were meant to show the frequencies for the emergency tuning of the radios in case of nuclear attack from the USSR..."

[TexasInstruments-2] [2]
Texas Instruments: TI Information Bulletin Citat: "...First Commercial Transistor Radio. TI Supplying Transistors for First "Pocket Size" Radio. DALLAS (October 18, 1954) - TI's part in the production of the first commercial transistorized radio receiver will be announced beginning today in newspapers throughout the country. The "pocket size" radio has four TI transistors. It also uses a TI subminiature output transformer...The receiver is being assembled and marketed by the Regency Division of Industrial Development Engineering Associates, Inc., Indianapolis. It will be available this week to the public through sales outlets in Los Angeles and New York City...TIers can justly be proud of being the first to produce a high-gain transistor at a cost permitting its application to the high-volume commercial market..."

[reyer-3] [3]
Website about the first transistor radioby Dr. Steven Reyer, a Professor in the Electrical Engineering and Computer Science Department at the Milwaukee School of Engineering, The Breakthrough Breadboard Feasibility Model: The Development of the First All-Transistor Radio,

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Transistorradio

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