|
Field-effect Tetrode
The tetrode field-effect transistor or field-effect tetrode is a solid-state semiconductor device, constructed by creating two field-effect channels back-to-back, with a junction between. It is a four-terminal device which does not have specific gate terminals because each channel is a gate for the other, the voltage conditions modulating the current carried by the other channel. Current–voltage relationship Where the voltage on the first channel is V_ - V_ and the voltage on the second channel is V_ - V_, the current in the first channel, I_, and the current in the second channel, I_, are given by: I_ = G_(V_ - V_) \left - \frac \frac \right/math> and I_ = G_(V_ - V_) \left - \frac \frac \right/math>, where the G_ are the low-voltage conductance of the channels and V_p is the pinch-off voltage (assumed to be the same for each channel). Applications The field-effect tetrode can be used as a highly linear electronically variable resistor – resistance is not modulated by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid-state Electronics
Solid-state electronics means semiconductor electronics: electronic equipment using semiconductor devices such as transistors, diodes and integrated circuits (ICs). The term is also used as an adjective for devices in which semiconductor electronics that have no moving parts replace devices with moving parts, such as the solid-state relay in which transistor switches are used in place of a moving-arm electromechanical relay, or the solid-state drive (SSD) a type of semiconductor memory used in computers to replace hard disk drives, which store data on a rotating disk. History The term "solid-state" became popular at the beginning of the semiconductor era in the 1960s to distinguish this new technology based on the transistor, in which the electronic action of devices occurred in a solid state, from previous electronic equipment that used vacuum tubes, in which the electronic action occurred in a gaseous state. A semiconductor device works by controlling an electric current ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor Device
A semiconductor device is an electronic component that relies on the electronic properties of a semiconductor material (primarily silicon, germanium, and gallium arsenide, as well as organic semiconductors) for its function. Its conductivity lies between conductors and insulators. Semiconductor devices have replaced vacuum tubes in most applications. They conduct electric current in the solid state, rather than as free electrons across a vacuum (typically liberated by thermionic emission) or as free electrons and ions through an ionized gas. Semiconductor devices are manufactured both as single discrete devices and as integrated circuit (IC) chips, which consist of two or more devices—which can number from the hundreds to the billions—manufactured and interconnected on a single semiconductor wafer (also called a substrate). Semiconductor materials are useful because their behavior can be easily manipulated by the deliberate addition of impurities, known as doping. Semi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Effect (semiconductor)
In physics, the field effect refers to the modulation of the electrical conductivity of a material by the application of an external electric field. In a metal, the electron density that responds to applied fields is so large that an external electric field can penetrate only a very short distance into the material. However, in a semiconductor the lower density of electrons (and possibly holes) that can respond to an applied field is sufficiently small that the field can penetrate quite far into the material. This field penetration alters the conductivity of the semiconductor near its surface, and is called the ''field effect''. The field effect underlies the operation of the Schottky diode and of field-effect transistors, notably the MOSFET, the JFET and the MESFET.The acronyms stand for ''M''etal ''O''xide ''S''emiconductor ''F''ield ''E''ffect ''T''ransistor, ''J''unction ''F''ield ''E''ffect ''T''ransistor, and ''ME''tal ''S''emiconductor ''F''ield ''E''ffect ''T''ransistor. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel Length Modulation
Channel length modulation (CLM) is an effect in field effect transistors, a shortening of the length of the inverted channel region with increase in drain bias for large drain biases. The result of CLM is an increase in current with drain bias and a reduction of output resistance. It is one of several short-channel effects in MOSFET scaling. It also causes distortion in JFET amplifiers. To understand the effect, first the notion of pinch-off of the channel is introduced. The channel is formed by attraction of carriers to the gate, and the current drawn through the channel is nearly a constant independent of drain voltage in saturation mode. However, near the drain, the gate ''and drain'' jointly determine the electric field pattern. Instead of flowing in a channel, beyond the pinch-off point the carriers flow in a subsurface pattern made possible because the drain and the gate both control the current. In the figure at the right, the channel is indicated by a dashed line and beco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Resistor
A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. The measuring instrument called a potentiometer is essentially a voltage divider used for measuring electric potential (voltage); the component is an implementation of the same principle, hence its name. Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Potentiometers operated by a mechanism can be used as position transducers, for example, in a joystick. Potentiometers are rarely used to directly control significant power (more than a watt), since the power dissipated in the potentiometer would be comparable to the power in the controlled load. Nomenclature There are a number of terms in the electronics industry used to describe certain types of potentiometers: * slide pot or slider pot: a potentiomete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bias Voltage
In electronics, biasing is the setting of DC (direct current) operating conditions (current and voltage) of an active device in an amplifier. Many electronic devices, such as diodes, transistors and vacuum tubes, whose function is processing time-varying ( AC) signals, also require a steady (DC) current or voltage at their terminals to operate correctly. This current or voltage is called ''bias''. The AC signal applied to them is superposed on this DC bias current or voltage. The operating point of a device, also known as bias point, quiescent point, or Q-point, is the DC voltage or current at a specified terminal of an active device (a transistor or vacuum tube) with no input signal applied. A bias circuit is a portion of the device's circuit which supplies this steady current or voltage. Overview In electronics, 'biasing' usually refers to a fixed DC voltage or current applied to a terminal of an electronic component such as a diode, transistor or vacuum tube in a circu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Junction Breakdown Voltage
The breakdown voltage of an insulator is the minimum voltage that causes a portion of an insulator to experience electrical breakdown and become electrically conductive. For diodes, the breakdown voltage is the minimum reverse voltage that makes the diode conduct appreciably in reverse. Some devices (such as TRIACs) also have a ''forward breakdown voltage''. Electrical breakdown Materials are often classified as conductors or insulators based on their resistivity. A conductor is a substance which contains many mobile charged particles called charge carriers which are free to move about inside the material. An electric field is created across a piece of the material by applying a voltage difference between electrical contacts on different sides of the material. The force of the field causes the charge carriers within the material to move, creating an electric current from the positive contact to the negative contact. For example, in metals one or more of the negatively charged ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inverse Proportion
In mathematics, two sequences of numbers, often experimental data, are proportional or directly proportional if their corresponding elements have a constant ratio, which is called the coefficient of proportionality or proportionality constant. Two sequences are inversely proportional if corresponding elements have a constant product, also called the coefficient of proportionality. This definition is commonly extended to related varying quantities, which are often called ''variables''. This meaning of ''variable'' is not the common meaning of the term in mathematics (see variable (mathematics)); these two different concepts share the same name for historical reasons. Two functions f(x) and g(x) are ''proportional'' if their ratio \frac is a constant function. If several pairs of variables share the same direct proportionality constant, the equation expressing the equality of these ratios is called a proportion, e.g., (for details see Ratio). Proportionality is closely rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depletion Layer
In semiconductor physics, the depletion region, also called depletion layer, depletion zone, junction region, space charge region or space charge layer, is an insulating region within a conductive, doped semiconductor material where the mobile charge carriers have been diffused away, or have been forced away by an electric field. The only elements left in the depletion region are ionized donor or acceptor impurities. This region of uncovered positive and negative ions is called the depletion region due to the depletion of carriers in this region. The depletion region is so named because it is formed from a conducting region by removal of all free charge carriers, leaving none to carry a current. Understanding the depletion region is key to explaining modern semiconductor electronics: diodes, bipolar junction transistors, field-effect transistors, and variable capacitance diodes all rely on depletion region phenomena. Formation in a p–n junction A depletion region for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuning Ratio
Tuning can refer to: Common uses * Tuning, the process of tuning a tuned amplifier or other electronic component * Musical tuning, musical systems of tuning, and the act of tuning an instrument or voice ** Guitar tunings ** Piano tuning, adjusting the pitch of pianos using a tuning fork or a frequency counter * Neuronal tuning, the property of brain cells to selectively represent a particular kind of sensory, motor or cognitive information * Radio tuning * Performance tuning - the optimization of systems, especially computer systems, which may include: ** Car tuning, an industry and hobby involving modifying automobile engines to improve their performance *** Engine tuning, the adjustment, modification, or design of internal combustion engines to yield more performance ** Computer hardware tuning ** Database tuning ** Self-tuning, a system capable of optimizing its own internal running parameters Arts, entertainment, and media * "Tuning", a song by Avail from their album ''Dixie'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field-effect Transistor
The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current in a semiconductor. FETs (JFETs or MOSFETs) are devices with three terminals: ''source'', ''gate'', and ''drain''. FETs control the flow of current by the application of a voltage to the gate, which in turn alters the conductivity between the drain and source. FETs are also known as unipolar transistors since they involve single-carrier-type operation. That is, FETs use either electrons (n-channel) or holes (p-channel) as charge carriers in their operation, but not both. Many different types of field effect transistors exist. Field effect transistors generally display very high input impedance at low frequencies. The most widely used field-effect transistor is the MOSFET (metal-oxide-semiconductor field-effect transistor). History The concept of a field-effect transistor (FET) was first patented by Austro-Hungarian physicist Julius Edgar Lilienfeld in 192 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multigate Device
A multigate device, multi-gate MOSFET or multi-gate field-effect transistor (MuGFET) refers to a metal–oxide–semiconductor field-effect transistor (MOSFET) that has more than one gate on a single transistor. The multiple gates may be controlled by a single gate electrode, wherein the multiple gate surfaces act electrically as a single gate, or by independent gate electrodes. A multigate device employing independent gate electrodes is sometimes called a multiple-independent-gate field-effect transistor (MIGFET). The most widely used multi-gate devices are the FinFET (fin field-effect transistor) and the GAAFET (gate-all-around field-effect transistor), which are non-planar transistors, or 3D transistors. Multi-gate transistors are one of the several strategies being developed by MOS semiconductor manufacturers to create ever-smaller microprocessors and memory cells, colloquially referred to as extending Moore's law (in its narrow, specific version concerning density scaling, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
