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Programmable Unijunction Transistor
A programmable unijunction transistor (PUT) is a three-lead electronic semiconductor device which is similar in its characteristics to a unijunction transistor, except that its behavior can be controlled using external components. In a unijunction transistor, the base region is divided into two parts by the emitter. The two parts of the base form a voltage divider, which sets the operating point of the UJT. That voltage divider can be programmed with two physical resistors connected to the gate terminal of the PUT. This allows the designer some control over the operating point of the PUT. Construction In construction, the programmable unijunction transistor is similar to the silicon controlled rectifier. It consists of four layers, two p-type layers and two n-type layers in equal proportion. Applications * It is used to trigger thyristors. * It is also used as a relaxation oscillator. As of 2012 ON Semiconductor onsemi (stylized in lowercase; legally ON Semiconductor Corporat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passivity (engineering)
Passivity is a property of engineering systems, most commonly encountered in analog electronics and control systems. Typically, analog designers use ''passivity'' to refer to incrementally passive components and systems, which are incapable of power gain. In contrast, control systems engineers will use ''passivity'' to refer to thermodynamically passive ones, which consume, but do not produce, energy. As such, without context or a qualifier, the term ''passive'' is ambiguous. An electronic circuit consisting entirely of passive components is called a passive circuit, and has the same properties as a passive component. If a component is ''not'' passive, then it is an active component. Thermodynamic passivity In control systems and circuit network theory, a passive component or circuit is one that consumes energy, but does not produce energy. Under this methodology, voltage and current sources are considered active, while resistors, capacitors, inductors, transistors, tunnel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energy, digital industry, additive manufacturing and venture capital and finance, but has since divested from several areas, now primarily consisting of the first four segments. In 2020, GE ranked among the Fortune 500 as the 33rd largest firm in the United States by gross revenue. In 2011, GE ranked among the Fortune 20 as the 14th most profitable company, but later very severely underperformed the market (by about 75%) as its profitability collapsed. Two employees of GE – Irving Langmuir (1932) and Ivar Giaever (1973) – have been awarded the Nobel Prize. On November 9, 2021, the company announced it would divide itself into three investment-grade public companies. On July 18, 2022, GE unveiled the brand names of the companies it will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PUT Symbol
Put or PUT may refer to: Finance * Put option, a financial contract between a buyer and a seller * CBOE S&P 500 PutWrite Index (ticker symbol) Science and technology * Programmable unijunction transistor Computing * Parameterized unit testing, in computer programming * Put, a Hypertext Transfer Protocol request method * Put, a File Transfer Protocol option to copy a file to a remote system; see List of FTP commands * Put, an output procedure in Pascal, Turing, and other programming languages ** In C, simple functions, puts and puts(), that put text on the screen Education * Petroleum University of Technology, Abadan, Ahvaz, Mahmud Abad and Tehran, Iran * Poznań University of Technology, Poland (Polish name: ''Politechnika Poznańska'') Transportation * Pui To stop (MTR station code), Hong Kong * Putney railway station (National Rail station code), London * Sri Sathya Sai Airport (IATA code), Puttaparthi, Andhra Pradesh, India Other uses * Phut or Put, Biblical grandson of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anode
An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ACID, for "anode current into device". The direction of conventional current (the flow of positive charges) in a circuit is opposite to the direction of electron flow, so (negatively charged) electrons flow out the anode of a galvanic cell, into an outside or external circuit connected to the cell. For example, the end of a household battery marked with a "-" (minus) is the anode. In both a galvanic cell and an electrolytic cell, the anode is the electrode at which the oxidation reaction occurs. In a galvanic cell the anode is the wire or plate having excess negative charge as a result of the oxidation reaction. In an electrolytic cell, the anode is the wire or plate upon which excess positive charge is imposed. As a result of this, anion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gate
A gate or gateway is a point of entry to or from a space enclosed by walls. The word derived from old Norse "gat" meaning road or path; But other terms include ''yett and port''. The concept originally referred to the gap or hole in the wall or fence, rather than a barrier which closed it. Gates may prevent or control the entry or exit of individuals, or they may be merely decorative. The moving part or parts of a gateway may be considered "doors", as they are fixed at one side whilst opening and closing like one. A gate may have a latch that can be raised and lowered to both open a gate or prevent it from swinging. Locks are also used on gates to increase the security. Larger gates can be used for a whole building, such as a castle or fortified town. Actual doors can also be considered gates when they are used to block entry as prevalent within a gatehouse. Today, many gate doors are opened by an automated gate operator. Purpose-specific types of gate * Baby gate a safety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathode
A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in which positive charges move. Electrons have a negative electrical charge, so the movement of electrons is opposite to that of the conventional current flow. Consequently, the mnemonic ''cathode current departs'' also means that electrons flow ''into'' the device's cathode from the external circuit. For example, the end of a household battery marked with a + (plus) is the cathode. The electrode through which conventional current flows the other way, into the device, is termed an anode. Charge flow Conventional current flows from cathode to anode outside of the cell or device (with electrons moving in the opposite direction), regardless of the cell or device type and operating mode. Cathode polarity with respect to the anode can be positive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UJT Caratteristica
A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch. The UJT is not used as a linear amplifier. It is used in free-running oscillators, synchronized or triggered oscillators, and pulse generation circuits at low to moderate frequencies (hundreds of kilohertz). It is widely used in the triggering circuits for silicon controlled rectifiers. In the 1960s, the low cost per unit, combined with its unique characteristic, warranted its use in a wide variety of applications like oscillators, pulse generators, saw-tooth generators, triggering circuits, phase control, timing circuits, and voltage- or current-regulated supplies.J. F. Cleary (ed.), ''General Electric Transistor Manual'', General Electric, 1964 Chapter 13 "Unijunction Transistor Circuits" The original unijunction transistor types are now considered obsolete, but a later multi-layer device, the programmable unijunction tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glass. Its electrical resistivity and conductivity, resistivity falls as its temperature rises; metals behave in the opposite way. Its conducting properties may be altered in useful ways by introducing impurities ("doping (semiconductor), doping") into the crystal structure. When two differently doped regions exist in the same crystal, a semiconductor junction is created. The behavior of charge carriers, which include electrons, ions, and electron holes, at these junctions is the basis of diodes, transistors, and most modern electronics. Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called "metalloid staircase" on the periodic table. After silicon, gallium arsenide is the second-most common s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unijunction Transistor
A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch. The UJT is not used as a linear amplifier. It is used in free-running oscillators, synchronized or triggered oscillators, and pulse generation circuits at low to moderate frequencies (hundreds of kilohertz). It is widely used in the triggering circuits for silicon controlled rectifiers. In the 1960s, the low cost per unit, combined with its unique characteristic, warranted its use in a wide variety of applications like oscillators, pulse generators, saw-tooth generators, triggering circuits, phase control, timing circuits, and voltage- or current-regulated supplies.J. F. Cleary (ed.), ''General Electric Transistor Manual'', General Electric, 1964 Chapter 13 "Unijunction Transistor Circuits" The original unijunction transistor types are now considered obsolete, but a later multi-layer device, the programmable unijunction tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage Divider
In electronics, a voltage divider (also known as a potential divider) is a passive linear circuit that produces an output voltage (''V''out) that is a fraction of its input voltage (''V''in). Voltage division is the result of distributing the input voltage among the components of the divider. A simple example of a voltage divider is two resistors connected in series, with the input voltage applied across the resistor pair and the output voltage emerging from the connection between them. Resistor voltage dividers are commonly used to create reference voltages, or to reduce the magnitude of a voltage so it can be measured, and may also be used as signal attenuators at low frequencies. For direct current and relatively low frequencies, a voltage divider may be sufficiently accurate if made only of resistors; where frequency response over a wide range is required (such as in an oscilloscope probe), a voltage divider may have capacitive elements added to compensate load capacitance. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Controlled Rectifier
A silicon controlled rectifier or semiconductor controlled rectifier is a four-layer solid-state current-controlling device. The name "silicon controlled rectifier" is General Electric's trade name for a type of thyristor. The principle of four-layer p–n–p–n switching was developed by Moll, Tanenbaum, Goldey, and Holonyak of Bell Laboratories in 1956. The practical demonstration of silicon controlled switching and detailed theoretical behavior of a device in agreement with the experimental results was presented by Dr Ian M. Mackintosh of Bell Laboratories in January 1958. The SCR was developed by a team of power engineers led by Gordon Hall and commercialized by Frank W. "Bill" Gutzwiller in 1957. Some sources define silicon-controlled rectifiers and thyristors as synonymous while other sources define silicon-controlled rectifiers as a proper subset of the set of thyristors; the latter being devices with at least four layers of alternating n- and p-type material. Accor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyristor
A thyristor () is a solid-state semiconductor device with four layers of alternating P- and N-type materials used for high-power applications. It acts exclusively as a bistable switch (or a latch), conducting when the gate receives a current trigger, and continuing to conduct until the voltage across the device is reversed biased, or until the voltage is removed (by some other means). There are two designs, differing in what triggers the conducting state. In a three-lead thyristor, a small current on its Gate lead controls the larger current of the Anode to Cathode path. In a two-lead thyristor, conduction begins when the potential difference between the Anode and Cathode themselves is sufficiently large (breakdown voltage). Some sources define silicon-controlled rectifier (SCR) and thyristor as synonymous. Other sources define thyristors as more complex devices that incorporate at least four layers of alternating N-type and P-type substrate. The first thyristor devices were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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