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Point-contact Transistor
The point-contact transistor was the first type of transistor to be successfully demonstrated. It was developed by research scientists John Bardeen and Walter Brattain at Bell Laboratories in December 1947. They worked in a group led by physicist William Shockley. The group had been working together on experiments and theories of electric field effects in solid state materials, with the aim of replacing vacuum tubes with a smaller device that consumed less power. The critical experiment, carried out on December 16, 1947, consisted of a block of germanium, a semiconductor, with two very closely spaced gold contacts held against it by a spring. Brattain attached a small strip of gold foil over the point of a plastic triangle — a configuration which is essentially a point-contact diode. He then carefully sliced through the gold at the tip of the triangle. This produced two electrically isolated gold contacts very close to each other. The piece of germanium used had a surface l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electrical power, power. The transistor is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more are found embedded in integrated circuits. Austro-Hungarian physicist Julius Edgar Lilienfeld proposed the concept of a field-effect transistor in 1926, but it was not possible to actually constru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipolar Junction Transistor
A bipolar junction transistor (BJT) is a type of transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor, uses only one kind of charge carrier. A bipolar transistor allows a small current injected at one of its terminals to control a much larger current flowing between the terminals, making the device capable of amplification or switching. BJTs use two p–n junctions between two semiconductor types, n-type and p-type, which are regions in a single crystal of material. The junctions can be made in several different ways, such as changing the doping of the semiconductor material as it is grown, by depositing metal pellets to form alloy junctions, or by such methods as diffusion of n-type and p-type doping substances into the crystal. The superior predictability and performance of junction transistors quickly displaced the original point-contact transistor. Diffused transistors, along wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transistor Types
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electrical power, power. The transistor is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more are found embedded in integrated circuits. Austro-Hungarian physicist Julius Edgar Lilienfeld proposed the concept of a field-effect transistor in 1926, but it was not possible to actually const ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transistron
A transistor is a semiconductor device with at least three terminals for connection to an electric circuit. In the common case, the third terminal controls the flow of current between the other two terminals. This can be used for amplification, as in the case of a radio receiver, or for rapid switching, as in the case of digital circuits. The transistor replaced the vacuum-tube triode, also called a (thermionic) valve, which was much larger in size and used significantly more power to operate.The first transistor was successfully demonstrated on December 23, 1947, at Bell Laboratories in Murray Hill, New Jersey. Bell Labs was the research arm of American Telephone and Telegraph (AT&T). The three individuals credited with the invention of the transistor were William Shockley, John Bardeen and Walter Brattain. The introduction of the transistor is often considered one of the most important inventions in history. Transistors are broadly classified into two categories: ''bipolar junct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duodiode
A transistor is a semiconductor device with at least three terminals for connection to an electric circuit. In the common case, the third terminal controls the flow of current between the other two terminals. This can be used for amplification, as in the case of a radio receiver, or for rapid switching, as in the case of digital circuits. The transistor replaced the vacuum-tube triode, also called a (thermionic) valve, which was much larger in size and used significantly more power to operate.The first transistor was successfully demonstrated on December 23, 1947, at Bell Laboratories in Murray Hill, New Jersey. Bell Labs was the research arm of American Telephone and Telegraph (AT&T). The three individuals credited with the invention of the transistor were William Shockley, John Bardeen and Walter Brattain. The introduction of the transistor is often considered one of the most important inventions in history. Transistors are broadly classified into two categories: ''bipolar ju ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Radio
A crystal radio receiver, also called a crystal set, is a simple radio receiver, popular in the early days of radio. It uses only the power of the received radio signal to produce sound, needing no external power. It is named for its most important component, a crystal detector, originally made from a piece of crystalline mineral such as galena. This component is now called a diode. Crystal radios are the simplest type of radio receiver and can be made with a few inexpensive parts, such as a wire for an antenna, a coil of wire, a capacitor, a crystal detector, and earphones (because a crystal set has insufficient power for a loudspeaker). However they are passive receivers, while other radios use an amplifier powered by current from a battery or wall outlet to make the radio signal louder. Thus, crystal sets produce rather weak sound and must be listened to with sensitive earphones, and can receive stations only within a limited range of the transmitter. The rectifying prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Logic
A logic gate is an idealized or physical device implementing a Boolean function, a logical operation performed on one or more Binary number, binary inputs that produces a single binary output. Depending on the context, the term may refer to an ideal logic gate, one that has for instance zero rise time and unlimited fan-out, or it may refer to a non-ideal physical device (see Ideal and real op-amps for comparison). Logic gates are primarily implemented using diodes or transistors acting as switch#Electronic switches, electronic switches, but can also be constructed using vacuum tubes, electromagnetic relays (relay logic), fluidic logic, pneumatics#Pneumatic logic, pneumatic logic, optics, molecular logic gate, molecules, or even analytical engine, mechanical elements. Now, most logic gates are made from MOSFETs (metal–oxide–semiconductor field-effect transistors). With amplification, logic gates can be cascaded in the same way that Boolean functions can be composed, allowing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Barrier Transistor
The surface-barrier transistor is a type of transistor developed by Philco in 1953 as an improvement to the alloy-junction transistor and the earlier point-contact transistor. Like the modern Schottky transistor, it offered much higher speed than earlier transistors and used metal–semiconductor junctions (instead of semiconductor–semiconductor junctions), but unlike the schottky transistor, both junctions were metal–semiconductor junctions. Production process Philco used a patented process of applying two tiny electrochemical jet streams of liquid indium sulfate (electrolyte solution) on opposite sides of a thin strip of N-type germanium base material. This process would etch away and form circular well depressions on each side of the N-type germanium base material, until the germanium base material was ultra thin and having a thickness of approximately a few ten-thousandths of an inch. After the etching process was finished, the polarity applied to the electrolyte was reve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negative Resistance
In electronics, negative resistance (NR) is a property of some electrical circuits and devices in which an increase in voltage across the device's terminals results in a decrease in electric current through it. This is in contrast to an ordinary resistor in which an increase of applied voltage causes a proportional increase in current due to Ohm's law, resulting in a positive resistance. While a positive resistance consumes power from current passing through it, a negative resistance produces power. Under certain conditions it can increase the power of an electrical signal, amplifying it. Negative resistance is an uncommon property which occurs in a few nonlinear electronic components. In a nonlinear device, two types of resistance can be defined: 'static' or 'absolute resistance', the ratio of voltage to current v / i, and ''differential resistance'', the ratio of a change in voltage to the resulting change in current \Delta v/\Delta i. The term negative resistance means ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha (α) And Beta (β)
Alpha (uppercase , lowercase ; grc, ἄλφα, ', or ell, άλφα, álfa) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter aleph , which is the West Semitic word for " ox". Letters that arose from alpha include the Latin letter A and the Cyrillic letter А. Uses Greek In Ancient Greek, alpha was pronounced and could be either phonemically long ( ː or short ( . Where there is ambiguity, long and short alpha are sometimes written with a macron and breve today: . * = ' "a time" * = ' "tongue" In Modern Greek, vowel length has been lost, and all instances of alpha simply represent the open front unrounded vowel . In the polytonic orthography of Greek, alpha, like other vowel letters, can occur with several diacritic marks: any of three accent symbols (), and either of two breathing marks (), as well as combinations of these. It can also combine with the iota subscript (). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germanium Diode
A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used. Among many uses, diodes are found in rect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capacitor
A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of a capacitor is known as capacitance. While some capacitance exists between any two electrical conductors in proximity in a circuit, a capacitor is a component designed to add capacitance to a circuit. The capacitor was originally known as the condenser, a term still encountered in a few compound names, such as the ''condenser microphone''. The physical form and construction of practical capacitors vary widely and many types of capacitor are in common use. Most capacitors contain at least two electrical conductors often in the form of metallic plates or surfaces separated by a dielectric medium. A conductor may be a foil, thin film, sintered bead of metal, or an electrolyte. The nonconducting dielectric acts to increase the capacitor's c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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