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.See also amplifier, buffer, Consent Decree, current, modulation, patent, power, rectifier, and signal. Large numbers of transistors are frequently interconnected with microcircuits and baked into a single integrated circuit, many of which can exist on a single circuit board in an electronic device such as a computer, switch, or router. General Electric, IBM, Sony, and Texas Instruments are but a few of the companies that wrote a check.
#TRANSISTOR DEFINITION LICENSE#
A transistor can act on a signal to perform a variety of functions such as amplification, rectification, modulation or demodulation, and buffering.The transistor was invented by William Shockley, John Bardeen, and Walter Britain of AT&T Bell Telephone Laboratories, in 1947, and quickly replaced the electron tube, or vacuum tube.As a result of the 1956 Consent Decree, AT&T was forced to license the patented transistor technology to any company for $25,000. A transistor can operate linearly, like an audio amplifier, or like a switch, rapidly opening and closing an electronic gate. Small signals applied between the base and the emitter control the larger currents and power from the collector, with a small change in the signal applied to the base producing a large and rapid change in the current flowing through the entire component. The collector circuit collects power from the external power source, the base acts like a control electrode, and the emitter emits the outbound signal. One outer region serves as the collector, the inner region as the base, and the other outer region as the emitter. A transistor comprises a semiconducting material, such as silicon or germanium, in three electrode regions with two junctions.The regions are alternately doped positive-negative-positive or negative-positivenegative in a semiconducting sandwich, so to speak.
A contraction of trans-resistor, a transistor is a solid-state active device that controls current flow.
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