Transistor radio
A transistor radio is a radio receiver in which only transistors are used as active components. In parlance, this means mainly portable, so-called case or pocket radios.
Compared to the tube radio , the transistor assembly made it possible for the first time to significantly reduce the weight, operating costs and size of the devices, which primarily contributed to the great market success of the transistor radio.
The first pocket radios with monaural sound reproduction were typically limited to the medium wave band from 540 to 1600 kHz or long wave reception due to the technical limitations of the first series transistors - but with the advances in transistor technology, transistor receivers quickly conquered all available radio bands .
The smallest representatives of the genus were also known under the names shirtpocket and coatpocket ; Unlike the portables , their small size enabled the owner to put them in shirt or coat pockets.
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About history
In 1953 the Düsseldorf company Intermetall , founded by the German physicist Herbert Mataré - with Heinrich Welker parallel to Bell Laboratories also inventor of the transistor - together with Jakob Michael in 1952 presented the world's first transistor radio at the Düsseldorf radio exhibition - over a year before Texas Instruments did Milestone claimed for itself.
Transistor Radios from the United States
Today's American electronics giant Texas Instruments (TI) still had a very small semiconductor division in 1954, which in 1951 acquired a license to manufacture germanium transistors for the small sum of 25,000 US dollars from Bell Laboratories , the holders of the transistor patent . The wait-and-see attitude of the radio and television industry with regard to the enormous market opportunities of the new transistor technology initially thwarted plans for mass transistor production. First the decisive idea of the then Texas Instruments Vice President Pat Haggerty , together with the Regency Division of IDEA (an acronym for Industrial Development Engineering Associates ) in Indianapolis a new kind of technical consumer item - today it would be called a "fun product" or a gadget - Developing a small transistor pocket radio for the mass market helped the germanium transistor achieve its breakthrough: on October 18, 1954, seven years after the invention of the revolutionary transistor , the first commercial transistor radio from the United States, the Regency TR-1, was launched announced by the Regency Division and extremely successfully for the Christmas of the same year on the market - the medium wave - superheterodyne with only four transistors, with its tiny for that time size and extremely limited sonic possibilities associated, was as trendy and luxurious high- Tech novelty dem At that time , the larger device type portable radio, which was still equipped with battery tubes, was hopelessly inferior in terms of performance in every respect, but despite the high price it rapidly developed into the coveted fashionable "market hit", which meant that the TR-1 was completely sold out nationwide by spring 1955.
In the summer of the same year, the fully transistorized 8TP with eight transistors, developed by the Raytheon company , appeared, and it went down in radio history as the first "serious" transistor radio. Due to the much more generous dimensions and the consequent elimination of the limitations of the construction, the fully transistorized portable radio shone with better reception performance, economy of power consumption and good sound properties.
The Japanese competition
Japan's industry, which was largely destroyed by heavy bombing during the Second World War , rose to become one of the leading export nations within a few years thanks to extensive American aid for reconstruction: after Japan regained its full sovereignty in 1952, the Japanese economic miracle began - similar to post-war Germany Beginning.
The typically Japanese tendency towards meticulous accuracy, precision and miniaturization played a central role in the success story of the Japanese electronics industry. In the 1950s there was the small electronics company Tokyo Tsushin Kogyo.LTD in Japan , which also had a transistor license acquired from Bell and correctly assessed the market potential of the new transistor radio. When the Regency Division gave up the production of the successful Regency TR-1 in 1955 due to the withdrawal of Texas Instruments, that was the initial spark for the two Japanese company founders Masaru Ibuka and Akio Morita to gain a foothold with their products on the US electronics market. After the first Japanese transistor radio appeared in Japan in 1955 with the Sony TR-55, the Japanese went on the export offensive two years later with the legendary TR-63.
With its dimensions of 112 × 71 × 32 mm it was the smallest shirt pocket in the world at the time and, with its low price, attractive design, high quality and performance, immediately gained a leading market position in the United States as well as in other Western countries - and initiated the long global dominance of the Japanese transistor radio era, in which numerous competitors from the country took part.
The product name of the TR-63 was given the catchy name SONY , which became the company name SONY in 1958 and marked the beginning of the unprecedented market success of one of today's largest global media and electronics groups.
Widespread among the less affluent prospective buyers were the 2-transistor reflex receivers , mainly from the Far East , which worked with clever circuit technology and multiple use of the then still costly transistors - comparable to the Audion . The lower number of components together with a simple receiving circuit - normally straight-ahead receivers with diode rectification - and naturally reduced receiving performance enabled particularly favorable pricing. The reflex receivers were therefore often offered in toy stores and were also known in Anglo-American countries as boy's radios .
First series transistor radios in the German radio industry
The first transistor radio of the West German electronics industry was presented at the industrial fair in Hanover in 1957: the company Akkord-Radio , Gerätebau A.Jäger & Söhne from Offenbach / Herxheim, Germany's first special factory for suitcase receivers, brought the medium-wave radio Akkord-Peggie onto the market, At that time still without the printed circuit , which has now been introduced everywhere in transistor technology , but with the free wiring adopted from tube technology.
Two years later, Sternchen appeared on the East German electronics market , the first transistor-based MW pocket radio, developed by VEB Stern-Radio Sonneberg, later also produced with GDR transistors by VEB Stern-Radio Berlin.
Transistor radio for the ultra-short wave band
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In 1948, a European radio conference took place in Copenhagen , at which the transmission frequencies for radio stations in the long and medium wave range were redistributed. The result of the protracted deliberations, the Copenhagen Wave Plan , came into force on March 15, 1950 and replaced the stipulations of the Montreux Radio Conference, which were adopted in 1939 but not implemented due to the war events and which greatly benefited the European radio pioneer Germany.
With the entry into force of the new wave plan, the situation changed. As the loser of the Second World War , post-war Germany was only granted a few frequencies that were unfavorable in terms of broadcasting technology. As a result, adequate coverage of radio subscribers in these frequency bands was a long way off - in September of the same year radio representatives, the broadcasting industry and the postal administration decided to introduce frequency-modulated VHF radio on the three-meter band from 87 MHz to 100 MHz ( VHF- Volume II ) for radio and a rapid expansion of the VHF transmission network was carried out. With an output of 250 watts , the first frequency-modulated VHF radio transmitter in Europe on the 90.1 MHz frequency began in Freimann near Munich on the last day of February 1949, broadcasting what was then the only program of the Bavarian Radio - the first FM radio stations suitable for everyday use. Tube series devices or “attachments” for converting existing AM receivers did not appear until 1950 at the first post-war radio exhibition in Düsseldorf, which was all about the new VHF technology.
Due to the high transmission frequencies and the frequency modulation , the new VHF radio was able to offer radio listeners a completely new acoustic dimension. Interference-free reception, improved dynamics and the broadening of the audio frequency band made a significant contribution to the steadily increasing sales of radio equipment; from then on, a radio without FM reception was almost impossible to sell.
Before the great sales successes, the radio industry initially had to carry out considerable development work, as the development stage of electronics technology at that time was still at a low level for the complicated control of VHF band II. Extensive experience was only available for VHF Band I , on which programs were regularly broadcast in Germany from 1935 to 1944 by the television station Paul Nipkow .
The comparatively high VHF frequencies were not yet accessible to the newly developed semiconductor component. Due to the low cut-off frequencies of the germanium transistors in the early stages of development of semiconductor production, devices with VHF reception areas were, for technical reasons, still equipped with a tube / transistor hybrid assembly in a transitional phase - in the higher-frequency circuit parts such as the high-frequency pre- and mixer stage, local - Oscillator , intermediate frequency stages , electron tubes continued to be indispensable.
In an extensive test project, the innovative West German electronics company Graetz faced the challenge of designing a fully transistorized VHF receiver in 1957. The development engineers used a US RCA type as the high-frequency transistor, which was developed on the basis of basic research by the Nobel laureate in physics at RCA, Herbert Kroemer . A prototype of the VHF radio was presented in the same year, but economical series production failed because of the considerable quality variation of the RCA transistors that still existed at the time.
Stable VHF transistors were only available in larger numbers from 1958 - with the TFM-151 , the Japanese company SONY succeeded in the first series production of an elaborate VHF / MW transistor receiver with 15 transistors, 8 of which were in the VHF section.
The market success of the transistor radio
The transistor radio gradually replaced the tube receiver , which worked with mechanically sensitive electron tubes , for which a sophisticated power supply was necessary, which resulted in high operating costs for mobile portable radios.
Despite great difficulties at the beginning, which mainly had to do with the still unfavorable technical properties and the high costs of transistor production, the emerging triumph of the transistor in radio electronics could not be stopped, parallel to this, the steady decline of the tube technology that had dominated electronics up to that point became apparent on.
The sales market for radio equipment, which grew rapidly in the post-war period, was given a further boost with the simultaneous further development of transistor technology and the great market success of the new transistor radios and, with exceptionally high rates of increase, helped the electronics industry to generate enormous sales - in addition, the increasing transistorization of electronic equipment was increasing Miniaturization of circuit technology exemplifies the way into the future of semiconductor electronics .
Socio-cultural backgrounds
In the midst of a highly developed listening culture that still existed at the time, which especially in the acoustic media - and especially in radio - conquered a broad platform in the 1950s and early 1960s, even before the gradual triumph of the optical medium “television” the transistor radio its golden age: the space-saving, efficient, very robust and extremely long-term stable semiconductor technology made possible the commercially highly successful mobile portable radio, which has been expanded by the leading industrial nations worldwide into an extremely powerful product line and gradually becomes a sounding symbol for independence, freedom and Rebellion of the first young post-war generation established.
Equipped with an often double-digit and therefore particularly prestigious number of transistors, it was the expensive "flagships", shining with stylish taste and undoubted charm, of some manufacturers that have long since disappeared from the market, most of which are nowadays almost unimaginable in terms of housing design, construction and quality level Electronic components (among other things, air rotary capacitors and precision bandpass filters were standard equipment at the time) were produced with a high degree of manual labor - carefully treated specimens from the 1960s work just as they did half a century ago without the slightest electrical readjustment.
In this eventful time of booming consumption, the German economic miracle with its social orientation towards the United States , high-quality transistor cases were an extremely sought-after status symbol among young people and clearly had cult status: they were the acoustic witnesses of the triumph of rock and beat music, which you can do without parental controls could take with you anywhere at any time and were on top of that the "big super" of the domestic living room neither in the sound nor in the on all radio bands (also in the often neglected AM areas, where stations such as Radio Luxemburg were popular in the European wave range ) existing enormous reception services.
Transistor radios and their advantages
The introduction of transistor technology in commercial radio sets, with the elimination of high voltages and high heat dissipation , triggered the opportunity for a profound and far-reaching miniaturization of almost the entire range of components required for circuit construction: the most striking advantages of transistor radio over the older tube receiver were therefore the minor ones Dimensions and light weight. In addition, there is the negligible heat development of the transistors - almost all long-term problems of the electronic components used in tube devices are related to the high power consumption and the unfavorable heat production of the heated electron tubes, which greatly accelerate the aging process of all components used.
Transistor devices, on the other hand, shine with a comparatively high long-term stability of the device electronics - due to their low voltage and current requirements, which enables problem-free, inexpensive and safe operation with the usual standard batteries , since an anode battery is unnecessary in tube operation .
1956 by the American company Energizer downright tiny for that time 9-volt block battery called 006P, which was developed specifically for transistor radios, is a typical example of the new revolutionary order of the transistor circuit periphery. The gradual replacement of the semiconductor material germanium by the thermally more stable silicon ensured a further increase in the operational reliability of the transistor radio .
In contrast to electron tubes , the transistor is a mechanically very robust, undemanding electronic component with an almost unlimited service life - due to this fact, transistors are soldered with their connecting wires directly in electronic circuits. With the exception of the sub-miniature tubes , tubes, which are real wearing parts, are socketed components that are integrated into their circuit environment with a typical plug-in socket for easy replacement - especially in the case of the battery tubes of mobile portable radios with filigree and fragile filaments, the sensitive tubes had to due to mechanical damage (the dreaded "Broken filament") are often replaced well before their natural wear limit.
technical basics
As with the older tube receivers, the simplest circuit of a transistor radio consists of two main components, a detector receiver and an amplifier . The use of an audion is somewhat more complex, but also with a stronger reception and better separation - both circuitry minimal concepts ( straight-ahead receivers ) were important in the prewar period for the inexpensive mass production of popular receivers , but they no longer played a role in industrial production in the post-war period due to their technical inadequacies. the predominantly used technical reception principle had not changed due to the change from the electron tube to the transistor, the electronics industry also consistently used the more complex and electronically far more powerful concept of the superheterodyne receiver (superheterodyne).
Like all classic radios, the transistor radio, just like the tube radio, is designed to receive terrestrial analog radio broadcasts - all of the radio electronics work according to analog principles. Only in the area of transmitter tuning, in connection with the increasing digitalization of electronics since the 1980s, has it been possible to establish a rasterized tuning of the local tuning oscillator ( PLL - synthesizer ), which, with modern capacitance diodes and digital display and storage options, facilitates the relatively imprecise setting procedure for the Transmitter with a variable capacitor or variometer , frequency scale, dial pointer and dial cord was considerably simplified and enabled a frequency-accurate transmitter setting and storage. The digital radio data system , officially introduced in 1988, again considerably expanded the display options in the area of VHF radio bands.
The radios commonly used today are actually transistor radios, but the individual transistors are now increasingly combined with other components in integrated circuits , which contributes to a significant reduction in production costs. With the extensive elimination of tube radios, the need for a special distinction disappeared and so the word “transistor radio” is rarely used today.
Social impact
The invention of the transistor radio brought great progress for global communication: Due to mass production and the simplest power supply, these are still affordable for almost everyone in many developing countries and often offer residents of the most remote regions as well as people with insufficient literacy the only chance to make contact to keep up with the rest of the world.
Many families could afford to buy a second or third radio. Listening to the radio, which was previously limited to the living room in many households, was now also possible in other rooms and accompanied, for example, housework in the kitchen. Car radios existed before transistor technology became available - but only through this did they become widespread, which in turn triggered new services such as traffic radio. Many young people also had access to their own radio, which they could then use to listen to their own favorite stations.
In the GDR , the transistor radio made it possible for many young people to receive "undesired" stations without their parents or others being able to control it. Listening to West transmitters on the street could lead to controls by the police or so-called “voluntary helpers” of the People's Police , possibly also to the blocking of the devices. In a phase of “socialist vigilante justice”, the judgment of the Potsdam District Court of January 15, 1959 went down in the history of the young GDR as a “suitcase radio judgment”: A man had heard the “west station” RIAS on his transistor radio on the street when he was him a passer-by asked to switch to a GDR channel. Because the radio owner did not comply with the request, the passer-by destroyed the device. The district court rejected the claim for damages on the grounds:
“According to § 228 BGB, the person who damages or destroys a foreign object is not acting illegally in order to avert an imminent danger caused by the foreign object for himself or for another. It can be proven that the plaintiff let the portable radio play so loud that other passers-by could also hear the RIAS hate speech. He is guilty of spreading agitation against our state. "
In the case of the NVA and the border troops of the GDR , the GDR stations had to be marked as permitted stations on the scale, if others were heard, there were penalties and the device could be confiscated.
The transistor radio also brought about a further development: stereophonic radio receivers became more handy and affordable, so that the increase in quality caused by stereophonic broadcasting became more widespread.
The installation of connection sockets for turntables and magnetic tape recorders made the transistor radio an inexpensive amplifier. With the development of small magnetic tape cassettes ( compact cassettes ) instead of the previous reel tapes , small tape recorders ( cassette recorders ) could be built. Since the late 1960s, this has led to combinations with compact cassette devices that were offered as radio recorders . This enabled the recording and playback of radio broadcasts and the exchange of music with just one device. Later, radio recorders developed into large portable stereo devices with a high output power and two cassette recorders, which made it possible to transfer music from one cassette to another at higher tape speeds. Finally, there were even devices with an additional CD player . The development of large portable devices is contrasted with miniaturization: first the Sony company built small stereo cassette sets, called Walkman , to which a built-in radio was soon added. Then mini radios without a cassette part were also developed. Today there are small radio receivers such. B. in cell phones and as an addition in MP3 players .
The low energy requirement of the transistor receiver enables alternative energy supply, for example with photocells or with a hand dynamo . This is particularly important in areas that are not connected to the power grid.
swell
- ^ How Europe Missed The Transistor - The most important invention of the 20th century was conceived not just once, but twice . In: IEEE Spectrum . November 1, 2005.
- ↑ Late honor for German Mister Transistor. In: The world . November 13, 2008.
- ↑ Falco Werkentin : "Law of the thumb - A new form of socialist administration of justice". In: Political criminal justice in the Ulbricht era. Berlin 1995, ISBN 3-86153-069-4 , p. 252 ff.
- Helmut Bergold, Peter Drehmann, Adolf Kraemer: Dorn-Bader Physics, upper level, 12/13 Grade level, basic courses and advanced courses . Schroedel, ISBN 3-507-86205-0 .
- Burkhard Kainka: Handicraft corner - the low-power radio module. Retrieved September 11, 2007 .
- The Regency TR-1 Family , Sony Transistor Radios , Vintage Micro Transistor Radios , American Shirt-Pocket Transistor Radios and more at EricWrobbel.com (English, paid)
literature
- Heike Weber: The promise of mobile freedom: on the cultural and technological history of portable radios, walkers and cell phones. (Science studies). transcript-Verlag, Bielefeld 2008, ISBN 978-3-89942-871-1 .
- 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. In: IEEE Spectrum. December 1985, pp. 64-69.
Web links
- Photos and information about old radios (English)
- Article on the Radio Regency TR-1 (english)
- TI Information Bulletin : First Commercial Transistor Radio October 18, 1954
- Pocket radios from 1954 to 1965 and their design (English)
- Early German transistor radios.