![]() ![]() Early transistors were "unstable" and only suitable for low-power, low-frequency applications, but as transistor design developed, these problems were slowly overcome. Another company liked the idea and also decided to take out a license, introducing their own radio under the brand name Sony. They also licensed it to a number of other electronics companies, including Texas Instruments, who produced a limited run of transistor radios as a sales tool. Pierce recalled the naming somewhat differently:īell put the transistor into production at Western Electric in Allentown, Pennsylvania. The rationale for the name is described in the following extract from the company's Technical Memorandum calling for votes: Bardeen eventually developed a new branch of surface physics to account for the "odd" behaviour they saw, and Bardeen and Brattain eventually succeeded in building a working device.īell Telephone Laboratories needed a generic name for the new invention: "Semiconductor Triode", "Solid Triode", "Surface States Triode", "Crystal Triode" and "Iotatron" were all considered, but "transistor," coined by John R. With this knowledge in hand they turned to the design of a triode, but found this was not at all easy. Early tube-based technology did not switch fast enough for this role, leading the Bell team to use solid state diodes instead. This work followed from their war-time efforts to produce extremely pure germanium "crystal" mixer diodes, used in radar units as a frequency mixer element in microwave radar receivers. On 22 December 1947 William Shockley, John Bardeen and Walter Brattain succeeded in building the first practical point-contact transistor at Bell Labs. It is not clear whether either design was ever built, and this is generally considered unlikely. Oskar Heil patented the field-effect transistor. The first patents for the transistor principle were registered in Germany in 1928 by Julius Edgar Lilienfeld. Areas influenced by the Digital Revolution include television, radio, and newspapers. As a result, today, much media data is delivered in digital form, finally being converted and presented in analog form by computers. With digital computers offering the ability to quickly find, sort and process digital information, more and more effort has been put into making information digital. It is often less expensive and more effective to use a standard microcontroller and write a computer program to carry out a control function than to design an equivalent mechanical control function.īecause of the low cost of transistors and hence digital computers, there is a trend to digitize information. Transistorized circuits have replaced electromechanical devices for the control of appliances and machinery as well. The transistor's low cost, flexibility and reliability have made it a universal device for non-mechanical tasks, such as digital computing. A logic gate comprises about twenty transistors whereas an advanced microprocessor, as of 2006, can use as many as 1.7 billion transistors (MOSFETs). Its importance in today's society rests on its ability to be mass produced using a highly automated process ( fabrication) that achieves vanishingly low per-transistor costs.Īlthough millions of individual (known as discrete) transistors are still used, the vast majority of transistors are fabricated into integrated circuits (also called microchips or simply chips) along with diodes, resistors, capacitors and other electronic components to produce complete electronic circuits. It is the key active component in practically all modern electronics. The transistor is considered by many to be one of the greatest inventions in modern history, ranking in importance with the printing press, automobile and telephone. Digital circuits include logic gates, random access memory (RAM), microprocessors, and digital signal processors (DSPs). Transistors are also used in digital circuits where they function as electronic switches. In analog circuits, transistors are used in amplifiers, (direct current amplifiers, audio amplifiers, radio frequency amplifiers), and linear regulated power supplies. Application of current in BJTs and voltage in FETs between the input and common terminals increases the conductivity between the common and output terminals, thereby controlling current flow between them.įor more details on the operation of these two types of transistors, see field effect transistor and bipolar junction transistor. Transistors are divided into two main categories: bipolar junction transistors (BJTs) and field effect transistors (FETs). The word transistor, coined by John Robinson Pierce in 1949, is a foreshortening of trans-resistance or transfer varistor (see the history section below). 6 Advantages of transistors over vacuum tubes. ![]()
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