1.
Electronic circuit
–
In an integrated circuit or IC, the components and interconnections are formed on the same substrate, typically a semiconductor such as silicon or gallium arsenide. An electronic circuit can usually be categorized as an analog circuit, breadboards, perfboards, and stripboards are common for testing new designs. They allow the designer to make changes to the circuit during development. Analog electronic circuits are those in current or voltage may vary continuously with time to correspond to the information being represented. Analog circuitry is constructed from two building blocks, series and parallel circuits. In a series circuit, the current passes through a series of components. A string of Christmas lights is an example of a series circuit, if one goes out. In a parallel circuit, all the components are connected to the voltage. The basic components of analog circuits are wires, resistors, capacitors, inductors, diodes, analog circuits are very commonly represented in schematic diagrams, in which wires are shown as lines, and each component has a unique symbol. Analog circuit analysis employs Kirchhoffs circuit laws, all the currents at a node, wires are usually treated as ideal zero-voltage interconnections, any resistance or reactance is captured by explicitly adding a parasitic element, such as a discrete resistor or inductor. When the circuit size is comparable to a wavelength of the relevant signal frequency, wires are treated as transmission lines, with constant characteristic impedance, and the impedances at the start and end determine transmitted and reflected waves on the line. These values represent the information that is being processed, in the vast majority of cases, binary encoding is used, one voltage represents a binary 1 and another voltage represents a binary 0. Digital circuits make extensive use of transistors, interconnected to create gates that provide the functions of Boolean logic, AND, NAND, OR, NOR, XOR. Digital circuits therefore can provide both logic and memory, enabling them to perform arbitrary computational functions, the design process for digital circuits is fundamentally different from the process for analog circuits. Each logic gate regenerates the binary signal, so the designer need not account for distortion, gain control, offset voltages, as a consequence, extremely complex digital circuits, with billions of logic elements integrated on a single silicon chip, can be fabricated at low cost. Such digital integrated circuits are ubiquitous in electronic devices, such as calculators, mobile phone handsets. Digital circuitry is used to general purpose computing chips, such as microprocessors. Field-programmable gate arrays, chips with logic circuitry whose configuration can be modified after fabrication, are widely used in prototyping
2.
Electronics
–
Electronics is the science of controlling electrical energy electrically, in which the electrons have a fundamental role. Commonly, electronic devices contain circuitry consisting primarily or exclusively of active semiconductors supplemented with passive elements, the science of electronics is also considered to be a branch of physics and electrical engineering. The ability of electronic devices to act as switches makes digital information processing possible, until 1950 this field was called radio technology because its principal application was the design and theory of radio transmitters, receivers, and vacuum tubes. Today, most electronic devices use semiconductor components to perform electron control and this article focuses on engineering aspects of electronics. Components are generally intended to be connected together, usually by being soldered to a circuit board. Components may be packaged singly, or in more complex groups as integrated circuits, some common electronic components are capacitors, inductors, resistors, diodes, transistors, etc. Components are often categorized as active or passive, vacuum tubes were among the earliest electronic components. They were almost solely responsible for the revolution of the first half of the Twentieth Century. They took electronics from parlor tricks and gave us radio, television, phonographs, radar, long distance telephony and they played a leading role in the field of microwave and high power transmission as well as television receivers until the middle of the 1980s. Since that time, solid state devices have all but completely taken over, vacuum tubes are still used in some specialist applications such as high power RF amplifiers, cathode ray tubes, specialist audio equipment, guitar amplifiers and some microwave devices. The 608 contained more than 3,000 germanium transistors, thomas J. Watson Jr. ordered all future IBM products to use transistors in their design. From that time on transistors were almost exclusively used for computer logic, circuits and components can be divided into two groups, analog and digital. A particular device may consist of circuitry that has one or the other or a mix of the two types, most analog electronic appliances, such as radio receivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a range of voltage or current as opposed to discrete levels as in digital circuits. The number of different analog circuits so far devised is huge, especially because a circuit can be defined as anything from a single component, analog circuits are sometimes called linear circuits although many non-linear effects are used in analog circuits such as mixers, modulators, etc. Good examples of analog circuits include vacuum tube and transistor amplifiers, one rarely finds modern circuits that are entirely analog. These days analog circuitry may use digital or even microprocessor techniques to improve performance and this type of circuit is usually called mixed signal rather than analog or digital. Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non-linear operation, an example is the comparator which takes in a continuous range of voltage but only outputs one of two levels as in a digital circuit
3.
Logical connective
–
The most common logical connectives are binary connectives which join two sentences which can be thought of as the functions operands. Also commonly, negation is considered to be a unary connective, logical connectives along with quantifiers are the two main types of logical constants used in formal systems such as propositional logic and predicate logic. Semantics of a logical connective is often, but not always, a logical connective is similar to but not equivalent to a conditional operator. In the grammar of natural languages two sentences may be joined by a grammatical conjunction to form a compound sentence. Some but not all such grammatical conjunctions are truth functions, for example, consider the following sentences, A, Jack went up the hill. B, Jill went up the hill, C, Jack went up the hill and Jill went up the hill. D, Jack went up the hill so Jill went up the hill, the words and and so are grammatical conjunctions joining the sentences and to form the compound sentences and. The and in is a connective, since the truth of is completely determined by and, it would make no sense to affirm. Various English words and word pairs express logical connectives, and some of them are synonymous, examples are, In formal languages, truth functions are represented by unambiguous symbols. These symbols are called logical connectives, logical operators, propositional operators, or, in classical logic, see well-formed formula for the rules which allow new well-formed formulas to be constructed by joining other well-formed formulas using truth-functional connectives. Logical connectives can be used to more than two statements, so one can speak about n-ary logical connective. For example, the meaning of the statements it is raining, comes from Booles interpretation of logic as an elementary algebra. True, the symbol 1 comes from Booles interpretation of logic as an algebra over the two-element Boolean algebra. False, the symbol 0 comes also from Booles interpretation of logic as a ring, some authors used letters for connectives at some time of the history, u. for conjunction and o. Such a logical connective as converse implication ← is actually the same as material conditional with swapped arguments, thus, in some logical calculi certain essentially different compound statements are logically equivalent. A less trivial example of a redundancy is the equivalence between ¬P ∨ Q and P → Q. There are sixteen Boolean functions associating the input truth values P and Q with four-digit binary outputs and these correspond to possible choices of binary logical connectives for classical logic. Different implementations of classical logic can choose different functionally complete subsets of connectives, One approach is to choose a minimal set, and define other connectives by some logical form, as in the example with the material conditional above
4.
Binary number
–
The base-2 system is a positional notation with a radix of 2. Because of its implementation in digital electronic circuitry using logic gates. Each digit is referred to as a bit, the modern binary number system was devised by Gottfried Leibniz in 1679 and appears in his article Explication de lArithmétique Binaire. Systems related to binary numbers have appeared earlier in multiple cultures including ancient Egypt, China, Leibniz was specifically inspired by the Chinese I Ching. The scribes of ancient Egypt used two different systems for their fractions, Egyptian fractions and Horus-Eye fractions, the method used for ancient Egyptian multiplication is also closely related to binary numbers. This method can be seen in use, for instance, in the Rhind Mathematical Papyrus, the I Ching dates from the 9th century BC in China. The binary notation in the I Ching is used to interpret its quaternary divination technique and it is based on taoistic duality of yin and yang. Eight trigrams and a set of 64 hexagrams, analogous to the three-bit and six-bit binary numerals, were in use at least as early as the Zhou Dynasty of ancient China. The Song Dynasty scholar Shao Yong rearranged the hexagrams in a format that resembles modern binary numbers, the Indian scholar Pingala developed a binary system for describing prosody. He used binary numbers in the form of short and long syllables, Pingalas Hindu classic titled Chandaḥśāstra describes the formation of a matrix in order to give a unique value to each meter. The binary representations in Pingalas system increases towards the right, the residents of the island of Mangareva in French Polynesia were using a hybrid binary-decimal system before 1450. Slit drums with binary tones are used to encode messages across Africa, sets of binary combinations similar to the I Ching have also been used in traditional African divination systems such as Ifá as well as in medieval Western geomancy. The base-2 system utilized in geomancy had long been applied in sub-Saharan Africa. Leibnizs system uses 0 and 1, like the modern binary numeral system, Leibniz was first introduced to the I Ching through his contact with the French Jesuit Joachim Bouvet, who visited China in 1685 as a missionary. Leibniz saw the I Ching hexagrams as an affirmation of the universality of his own beliefs as a Christian. Binary numerals were central to Leibnizs theology and he believed that binary numbers were symbolic of the Christian idea of creatio ex nihilo or creation out of nothing. Is not easy to impart to the pagans, is the ex nihilo through Gods almighty power. In 1854, British mathematician George Boole published a paper detailing an algebraic system of logic that would become known as Boolean algebra
5.
Operational amplifier
–
An operational amplifier is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op-amp produces a potential that is typically hundreds of thousands of times larger than the potential difference between its input terminals. Operational amplifiers had their origins in analog computers, where they were used to perform operations in many linear, non-linear. The popularity of the op-amp as a block in analog circuits is due to its versatility. Op-amps are among the most widely used electronic devices today, being used in a vast array of consumer, industrial, op-amps may be packaged as components, or used as elements of more complex integrated circuits. The op-amp is one type of differential amplifier, other types of differential amplifier include the fully differential amplifier, the instrumentation amplifier, the isolation amplifier, and negative feedback amplifier. The output voltage of the op-amp Vout is given by the equation, situations in which the output voltage is equal to or greater than the supply voltage are referred to as saturation of the amplifier. The magnitude of AOL is not well controlled by the manufacturing process, without negative feedback, and perhaps with positive feedback for regeneration, an op-amp acts as a comparator. Since there is no feedback from the output to either input, if predictable operation is desired, negative feedback is used, by applying a portion of the output voltage to the inverting input. The closed loop feedback greatly reduces the gain of the circuit, when negative feedback is used, the circuits overall gain and response becomes determined mostly by the feedback network, rather than by the op-amp characteristics. The transfer functions are important in most applications of op-amps, such as in analog computers, high input impedance at the input terminals and low output impedance at the output terminal are particularly useful features of an op-amp. In the non-inverting amplifier on the right, the presence of negative feedback via the voltage divider Rf, equilibrium will be established when Vout is just sufficient to reach around and pull the inverting input to the same voltage as Vin. The voltage gain of the circuit is thus 1 + Rf/Rg. As a simple example, if Vin =1 V and Rf = Rg, Vout will be 2 V, because of the feedback provided by the Rf, Rg network, this is a closed loop circuit. The input impedance between and pins is much larger than other resistances in the circuit, the input signal Vin appears at both and pins, resulting in a current i through Rg equal to Vin/Rg. These ideals can be summarized by the two rules, The first rule only applies in the usual case where the op-amp is used in a closed-loop design. These rules are used as a good first approximation for analyzing or designing op-amp circuits. None of these ideals can be perfectly realized, a real op-amp may be modeled with non-infinite or non-zero parameters using equivalent resistors and capacitors in the op-amp model
6.
Diode
–
In electronics, a diode is a two-terminal electronic component that conducts primarily in one direction, it has low resistance to the current in one direction, and high resistance in the other. A semiconductor diode, the most common today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. A vacuum tube diode has two electrodes, a plate and a heated cathode, semiconductor diodes were the first semiconductor electronic devices. The discovery of crystals rectifying abilities was made by German physicist Ferdinand Braun in 1874, the first semiconductor diodes, called cats whisker diodes, developed around 1906, were made of mineral crystals such as galena. Today, most diodes are made of silicon, but other such as selenium and germanium are sometimes used. The most common function of a diode is to allow a current to pass in one direction. Thus, the diode can be viewed as a version of a check valve. However, diodes can have complicated behavior than this simple on–off action. Semiconductor diodes begin conducting electricity only if a threshold voltage or cut-in voltage is present in the forward direction. The voltage drop across a forward-biased diode varies only a little with the current, and is a function of temperature, a semiconductor diodes current–voltage characteristic can be tailored by selecting the semiconductor materials and the doping impurities introduced into the materials during manufacture. These techniques are used to create special-purpose diodes that perform different functions. Tunnel, Gunn and IMPATT diodes exhibit negative resistance, which is useful in microwave, Diodes, both vacuum and semiconductor, can be used as shot-noise generators. Thermionic diodes and solid state diodes were developed separately, at approximately the time, in the early 1900s. Until the 1950s vacuum tube diodes were used frequently in radios because the early point-contact type semiconductor diodes were less stable. In 1873, Frederick Guthrie discovered the principle of operation of thermionic diodes. Guthrie discovered that a positively charged electroscope could be discharged by bringing a piece of white-hot metal close to it. The same did not apply to a negatively charged electroscope, indicating that the current flow was possible in one direction. Thomas Edison independently rediscovered the principle on February 13,1880, at the time, Edison was investigating why the filaments of his carbon-filament light bulbs nearly always burned out at the positive-connected end
7.
Transistor
–
A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit, a voltage or current applied to one pair of the transistors terminals controls the current through another pair of terminals. Because the controlled power can be higher than the controlling power, today, some transistors are packaged individually, but many more are found embedded in integrated circuits. The transistor is the building block of modern electronic devices. Julius Edgar Lilienfeld patented a field-effect transistor in 1926 but it was not possible to construct a working device at that time. The first practically implemented device was a point-contact transistor invented in 1947 by American physicists John Bardeen, Walter Brattain, the transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things. The transistor is on the list of IEEE milestones in electronics, and Bardeen, Brattain, the thermionic triode, a vacuum tube invented in 1907, enabled amplified radio technology and long-distance telephony. The triode, however, was a device that consumed a substantial amount of power. Physicist Julius Edgar Lilienfeld filed a patent for a transistor in Canada in 1925. Lilienfeld also filed patents in the United States in 1926 and 1928. However, Lilienfeld did not publish any research articles about his devices nor did his patents cite any examples of a working prototype. In 1934, German inventor Oskar Heil patented a device in Europe. Solid State Physics Group leader William Shockley saw the potential in this, the term transistor was coined by John R. Pierce as a contraction of the term transresistance. Instead, what Bardeen, Brattain, and Shockley invented in 1947 was the first point-contact transistor, Mataré had previous experience in developing crystal rectifiers from silicon and germanium in the German radar effort during World War II. Using this knowledge, he began researching the phenomenon of interference in 1947, realizing that Bell Labs scientists had already invented the transistor before them, the company rushed to get its transistron into production for amplified use in Frances telephone network. The first bipolar junction transistors were invented by Bell labs William Shockley, on April 12,1950, Bell Labs chemists Gordon Teal and Morgan Sparks had successfully produced a working bipolar NPN junction amplifying germanium transistor. Bell Labs had made this new sandwich transistor discovery announcement, in a release on July 4,1951. The first high-frequency transistor was the surface-barrier germanium transistor developed by Philco in 1953 and these were made by etching depressions into an N-type germanium base from both sides with jets of Indium sulfate until it was a few ten-thousandths of an inch thick
8.
Switch
–
In electrical engineering, a switch is an electrical component that can make or break an electrical circuit, interrupting the current or diverting it from one conductor to another. The mechanism of a switch removes or restores the conducting path in a circuit when it is operated, the most familiar form of switch is a manually operated electromechanical device with one or more sets of electrical contacts, which are connected to external circuits. The mechanism actuating the transition between two states can be either a toggle or momentary type. A switch may be manipulated by a human as a control signal to a system, such as a computer keyboard button, or to control power flow in a circuit. Switches may be operated by process variables such as pressure, temperature, flow, current, voltage, for example, a thermostat is a temperature-operated switch used to control a heating process. A switch that is operated by electrical circuit is called a relay. Large switches may be operated by a motor drive mechanism. An ideal switch would have no voltage drop when closed, and it would have zero rise time and fall time during state changes, and would change state without bouncing between on and off positions. Practical switches fall short of ideal, they have resistance, limits on the current and voltage they can handle, finite switching time. The ideal switch is used in circuit analysis as it greatly simplifies the system of equations to be solved. Theoretical treatment of the effects of non-ideal properties is required in the design of networks of switches. In the simplest case, a switch has two pieces, often metal, called contacts, connected to an external circuit, that touch to complete the circuit. The contact material is chosen for its resistance to corrosion, because most metals form insulating oxides that would prevent the switch from working, contact materials are also chosen on the basis of electrical conductivity, hardness, mechanical strength, low cost and low toxicity. Sometimes the contacts are plated with noble metals and they may be designed to wipe against each other to clean off any contamination. Nonmetallic conductors, such as plastic, are sometimes used. To prevent the formation of insulating oxides, a minimum wetting current may be specified for a given switch design, in electronics, switches are classified according to the arrangement of their contacts. A pair of contacts is said to be closed when current can flow from one to the other, when the contacts are separated by an insulating air gap, they are said to be open, and no current can flow between them at normal voltages. The terms make for closure of contacts and break for opening of contacts are also widely used, the terms pole and throw are also used to describe switch contact variations
9.
Vacuum tube
–
In electronics, a vacuum tube, an electron tube, or just a tube, or valve, is a device that controls electric current between electrodes in an evacuated container. Vacuum tubes mostly rely on thermionic emission of electrons from a hot filament or a cathode heated by the filament and this type is called a thermionic tube or thermionic valve. A phototube, however, achieves electron emission through the photoelectric effect, the simplest vacuum tube, the diode, contains only a heater, a heated electron-emitting cathode, and a plate. Current can only flow in one direction through the device between the two electrodes, as electrons emitted by the travel through the tube and are collected by the anode. Adding one or more control grids within the tube allows the current between the cathode and anode to be controlled by the voltage on the grid or grids, Tubes with grids can be used for many purposes, including amplification, rectification, switching, oscillation, and display. In the 1940s the invention of devices made it possible to produce solid-state devices, which are smaller, more efficient, more reliable, more durable. Hence, from the mid-1950s solid-state devices such as transistors gradually replaced tubes, the cathode-ray tube remained the basis for televisions and video monitors until superseded in the 21st century. However, there are still a few applications for which tubes are preferred to semiconductors, for example, the used in microwave ovens. One classification of vacuum tubes is by the number of active electrodes, a device with two active elements is a diode, usually used for rectification. Devices with three elements are used for amplification and switching. Additional electrodes create tetrodes, pentodes, and so forth, which have additional functions made possible by the additional controllable electrodes. X-ray tubes are vacuum tubes. Phototubes and photomultipliers rely on electron flow through a vacuum, though in those cases electron emission from the cathode depends on energy from photons rather than thermionic emission, since these sorts of vacuum tubes have functions other than electronic amplification and rectification they are described in their own articles. A vacuum tube consists of two or more electrodes in a vacuum inside an airtight enclosure, most tubes have glass envelopes, though ceramic and metal envelopes have been used. The electrodes are attached to leads which pass through the envelope via an airtight seal, Tubes were a frequent cause of failure in electronic equipment, and consumers were expected to be able to replace tubes themselves. In addition to the terminals, some tubes had an electrode terminating at a top cap. The principal reason for doing this was to avoid leakage resistance through the tube base, the bases were commonly made with phenolic insulation which performs poorly as an insulator in humid conditions. There was even a design that had two top cap connections
10.
Relay
–
A relay is an electrically operated switch. Many relays use an electromagnet to operate a switch, but other operating principles are also used. Relays are used where it is necessary to control a circuit by a separate low-power signal, the first relays were used in long distance telegraph circuits as amplifiers, they repeated the signal coming in from one circuit and re-transmitted it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations, a type of relay that can handle the high power required to directly control an electric motor or other loads is called a contactor. Solid-state relays control power circuits with no moving parts, instead using a device to perform switching. Magnetic latching relays require one pulse of power to move their contacts in one direction. Repeated pulses from the same input have no effect, magnetic latching relays are useful in applications where interrupted power should not be able to transition the contacts. Magnetic latching relays can have single or dual coils. On a single device, the relay will operate in one direction when power is applied with one polarity. On a dual coil device, when polarized voltage is applied to the coil the contacts will transition. AC controlled magnetic latch relays have single coils that employ steering diodes to differentiate between operate and reset commands, american scientist Joseph Henry is often claimed to have invented a relay in 1835 in order to improve his version of the electrical telegraph, developed earlier in 1831. However, there is little in the way of documentation to suggest he had made the discovery prior to 1837. It is claimed that English inventor Edward Davy certainly invented the electric relay in his electric telegraph c.1835, a simple device, which is now called a relay, was included in the original 1840 telegraph patent of Samuel Morse. The mechanism described acted as an amplifier, repeating the telegraph signal. This overcame the problem of limited range of earlier telegraphy schemes, the word relay appears in the context of electromagnetic operations from 1860. The armature is hinged to the yoke and mechanically linked to one or more sets of moving contacts, the armature is held in place by a spring so that when the relay is de-energized there is an air gap in the magnetic circuit. In this condition, one of the two sets of contacts in the relay pictured is closed, and the set is open. Other relays may have more or fewer sets of contacts depending on their function, the relay in the picture also has a wire connecting the armature to the yoke
11.
Relay logic
–
Relay logic is a method of implementing combinational logic in electrical control circuits by using several electrical relays wired in a particular configuration. The schematic diagrams for relay logic circuits are often called line diagrams, a relay logic circuit is an electrical network consisting of lines, or rungs, in which each line or rung must have continuity to enable the output device. A typical circuit consists of a number of rungs, with each controlling a output. This output is controlled by a combination of input or output conditions, such as input switches, the conditions that represent the inputs are connected in series, parallel, or series-parallel to obtain the logic required to drive the output. The relay logic circuit forms an electrical schematic diagram for the control of input and output devices, relay logic diagrams represent the physical interconnection of devices. Each rung would have a unique identifying number and the individual wires on that rung would have wire numbers as a derivative of the rung number. Thus, if a rung was labelled as 105, the first independent wire would be 1051, the second as 1052, a wire would be named for the top most rung to which it connected, even if it branched to lower rungs. When designing a system, it was practice to skip numbers for the rungs to allow later additions as required. When the rack was manufactured, as a wire was installed and this also applied for pulling wire into the factory through conduit or in trays where each wire would have corresponding numbers. Wire labels were typically pieces of tape with numbers or letters printed onto them and collected in small. A number strip would be peeled out and wrapped around the wire near the end, wire numbers were made up of a series of the number strips so wire 1051 would be four strips. There are also pocket sized printers that print onto an adhesive backed label that can be wrapped around the wire, the basic format for relay logic diagrams is as follows,1. The two vertical lines that all devices on the relay logic diagram are labeled L1 and L2. The space between L1 and L2 represents the voltage of the control circuit, output devices are always connected to L2. Any electrical overloads that are to be included must be shown between the device and L2, otherwise, the output device must be the last component before L2. Control devices are shown between L1 and the output device. Control devices may be connected either in series or in parallel with each other, devices which perform a STOP function are usually connected in series, while devices that perform a START function are connected in parallel. Electrical devices are shown in their normal conditions, an NC contact would be shown as normally closed, and an NO contact would appear as a normally open device
12.
Fluidics
–
Fluidics, or fluidic logic, is the use of a fluid to perform analog or digital operations similar to those performed with electronics. The physical basis of fluidics is pneumatics and hydraulics, based on the foundation of fluid dynamics. The 1960s saw the application of fluidics to sophisticated control systems, a jet of fluid can be deflected by a weaker jet striking it at the side. This provides nonlinear amplification, similar to the used in electronic digital logic. It is used mostly in environments where electronic digital logic would be unreliable, nanotechnology considers fluidics as one of its instruments. In this domain, effects such as fluid-solid and fluid-fluid interface forces are highly significant. Fluidics have also used for military applications. Logic gates can be built that use water instead of electricity to power the gating function and these are reliant on being positioned in one orientation to perform correctly. An OR gate is simply two pipes being merged, and a NOT gate consists of A deflecting a supply stream to produce Ā, the AND and XOR gates are sketched in the diagram. An inverter could also be implemented with the XOR gate, as A XOR1 = Ā, bubble logic is another kind of fluidic logic. Bubble logic gates conserve the number of entering and exiting the device, since bubbles are neither produced nor destroyed in the logic operation. In a fluidic amplifier, A fluid supply, which may be air, water, or hydraulic fluid, pressure applied to the control ports C1 or C2 deflects the stream, so that it exits via either port O1 or O2. The stream entering the ports may be much weaker than the stream being deflected. Given this basic device, flip flops and other fluidic logic elements can be constructed, simple systems of digital logic can thus be built. Fluidic amplifiers typically have bandwidths in the low range, so systems built from them are quite slow compared to electronic devices. The fluidic triode is a device that uses a fluid to convey the signal. Although much studied in the laboratory they have few practical applications, many expect them to be key elements of nanotechnology. Fluidic triodes were used as the stage in the main Public Address system at the 1964 New York Worlds Fair
13.
Pneumatics
–
Pneumatics is a branch of engineering that makes use of gas or pressurized air. Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases, a centrally located and electrically powered compressor powers cylinders, air motors, and other pneumatic devices. A pneumatic system controlled through manual or automatic solenoid valves is selected when it provides a lower cost, more flexible, pneumatics also has applications in dentistry, construction, mining, and other areas. Pneumatic systems in fixed installations, such as factories, use compressed air because a sustainable supply can be made by compressing atmospheric air, the air usually has moisture removed, and a small quantity of oil is added at the compressor to prevent corrosion and lubricate mechanical components. Factory-plumbed pneumatic-power users need not worry about poisonous leakage, as the gas is usually just air, smaller or stand-alone systems can use other compressed gases that present an asphyxiation hazard, such as nitrogen—often referred to as OFN when supplied in cylinders. Any compressed gas other than air is an asphyxiation hazard—including nitrogen, compressed oxygen would not asphyxiate, but is not used in pneumatically-powered devices because it is a fire hazard, more expensive, and offers no performance advantage over air. Carbon dioxide is an asphyxiant and can be a hazard if vented improperly. The origins of pneumatics can be traced back to the first century when ancient Greek mathematician Hero of Alexandria wrote about his inventions powered by steam or the wind, german physicist Otto von Guericke went a little further. He invented the pump, a device that can draw out air or gas from the attached vessel. He demonstrated the vacuum pump to separate the pairs of copper hemispheres using air pressures, the field of pneumatics has changed considerably over the years. It has moved from small handheld devices to large machines with multiple parts that serve different functions, both pneumatics and hydraulics are applications of fluid power. Pneumatics uses an easily compressible gas such as air or a suitable pure gas—while hydraulics uses relatively incompressible liquid media such as oil, most industrial pneumatic applications use pressures of about 80 to 100 pounds per square inch. Hydraulics applications commonly use from 1,000 to 5,000 psi, simplicity of design and control—Machines are easily designed using standard cylinders and other components, and operate via simple on-off control. Reliability—Pneumatic systems generally have long operating lives and require little maintenance, because gas is compressible, equipment is less subject to shock damage. Gas absorbs excessive force, whereas fluid in hydraulics directly transfers force, compressed gas can be stored, so machines still run for a while if electrical power is lost. Safety—There is a low chance of fire compared to hydraulic oil. Newer machines are usually overload safe, liquid does not absorb any of the supplied energy. Capable of moving much higher loads and providing much higher due to the incompressibility
14.
Optics
–
Optics is the branch of physics which involves the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light, because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for using the classical description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice, practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines, physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be accounted for in geometric optics. Historically, the model of light was developed first, followed by the wave model of light. Progress in electromagnetic theory in the 19th century led to the discovery that waves were in fact electromagnetic radiation. Some phenomena depend on the fact that light has both wave-like and particle-like properties, explanation of these effects requires quantum mechanics. When considering lights particle-like properties, the light is modelled as a collection of particles called photons, quantum optics deals with the application of quantum mechanics to optical systems. Optical science is relevant to and studied in many related disciplines including astronomy, various engineering fields, photography, practical applications of optics are found in a variety of technologies and everyday objects, including mirrors, lenses, telescopes, microscopes, lasers, and fibre optics. Optics began with the development of lenses by the ancient Egyptians and Mesopotamians, the earliest known lenses, made from polished crystal, often quartz, date from as early as 700 BC for Assyrian lenses such as the Layard/Nimrud lens. The ancient Romans and Greeks filled glass spheres with water to make lenses, the word optics comes from the ancient Greek word ὀπτική, meaning appearance, look. Greek philosophy on optics broke down into two opposing theories on how vision worked, the theory and the emission theory. The intro-mission approach saw vision as coming from objects casting off copies of themselves that were captured by the eye, plato first articulated the emission theory, the idea that visual perception is accomplished by rays emitted by the eyes. He also commented on the parity reversal of mirrors in Timaeus, some hundred years later, Euclid wrote a treatise entitled Optics where he linked vision to geometry, creating geometrical optics. Ptolemy, in his treatise Optics, held a theory of vision, the rays from the eye formed a cone, the vertex being within the eye. The rays were sensitive, and conveyed back to the observer’s intellect about the distance. He summarised much of Euclid and went on to describe a way to measure the angle of refraction, during the Middle Ages, Greek ideas about optics were resurrected and extended by writers in the Muslim world
15.
Analytical Engine
–
The Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician and computer pioneer Charles Babbage. It was first described in 1837 as the successor to Babbages difference engine, in other words, the logical structure of the Analytical Engine was essentially the same as that which has dominated computer design in the electronic era. Babbage was never able to complete construction of any of his machines due to conflicts with his chief engineer and it was not until the 1940s that the first general-purpose computers were actually built, more than a century after Babbage had proposed the pioneering Analytical Engine in 1837. Construction of this machine was never completed, Babbage had conflicts with his engineer, Joseph Clement. During this project, he realized that a more general design. The work on the design of the Analytical Engine started in 1835, the input, consisting of programs and data was to be provided to the machine via punched cards, a method being used at the time to direct mechanical looms such as the Jacquard loom. For output, the machine would have a printer, a curve plotter, the machine would also be able to punch numbers onto cards to be read in later. It employed ordinary base-10 fixed-point arithmetic, there was to be a store capable of holding 1,000 numbers of 40 decimal digits each. An arithmetical unit would be able to all four arithmetic operations, plus comparisons. Initially it was conceived as a difference engine curved back upon itself, in a circular layout. Later drawings depict a regularized grid layout, the programming language to be employed by users was akin to modern day assembly languages. Loops and conditional branching were possible, and so the language as conceived would have been Turing-complete as later defined by Alan Turing, there were three separate readers for the three types of cards. Babbage developed some two dozen programs for the Analytical Engine between 1837 and 1840, and one program later and these programs treat polynomials, iterative formulas, Gaussian elimination, and Bernoulli numbers. In 1842, the Italian mathematician Luigi Federico Menabrea published a description of the based on a lecture by Babbage in French. In 1843, the description was translated into English and extensively annotated by Ada Lovelace, in recognition of her additions to Menabreas paper, which included a way to calculate Bernoulli numbers using the machine, she has been described as the first computer programmer. Late in his life, Babbage sought ways to build a version of the machine. In 1878, a committee of the British Association for the Advancement of Science described the Analytical Engine as a marvel of mechanical ingenuity, but recommended against constructing it. The committee acknowledged the usefulness and value of the machine, but could not estimate the cost of building it, and were unsure whether the machine would function correctly after being built
16.
Boolean algebra
–
In mathematics and mathematical logic, Boolean algebra is the branch of algebra in which the values of the variables are the truth values true and false, usually denoted 1 and 0 respectively. It is thus a formalism for describing logical relations in the way that ordinary algebra describes numeric relations. Boolean algebra was introduced by George Boole in his first book The Mathematical Analysis of Logic, according to Huntington, the term Boolean algebra was first suggested by Sheffer in 1913. Boolean algebra has been fundamental in the development of digital electronics and it is also used in set theory and statistics. Booles algebra predated the modern developments in algebra and mathematical logic. In an abstract setting, Boolean algebra was perfected in the late 19th century by Jevons, Schröder, Huntington, in fact, M. H. Stone proved in 1936 that every Boolean algebra is isomorphic to a field of sets. Shannon already had at his disposal the abstract mathematical apparatus, thus he cast his switching algebra as the two-element Boolean algebra, in circuit engineering settings today, there is little need to consider other Boolean algebras, thus switching algebra and Boolean algebra are often used interchangeably. Efficient implementation of Boolean functions is a problem in the design of combinational logic circuits. Logic sentences that can be expressed in classical propositional calculus have an equivalent expression in Boolean algebra, thus, Boolean logic is sometimes used to denote propositional calculus performed in this way. Boolean algebra is not sufficient to capture logic formulas using quantifiers, the closely related model of computation known as a Boolean circuit relates time complexity to circuit complexity. Whereas in elementary algebra expressions denote mainly numbers, in Boolean algebra they denote the truth values false and these values are represented with the bits, namely 0 and 1. Addition and multiplication then play the Boolean roles of XOR and AND respectively, Boolean algebra also deals with functions which have their values in the set. A sequence of bits is a commonly used such function, another common example is the subsets of a set E, to a subset F of E is associated the indicator function that takes the value 1 on F and 0 outside F. The most general example is the elements of a Boolean algebra, as with elementary algebra, the purely equational part of the theory may be developed without considering explicit values for the variables. The basic operations of Boolean calculus are as follows, AND, denoted x∧y, satisfies x∧y =1 if x = y =1 and x∧y =0 otherwise. OR, denoted x∨y, satisfies x∨y =0 if x = y =0, NOT, denoted ¬x, satisfies ¬x =0 if x =1 and ¬x =1 if x =0. Alternatively the values of x∧y, x∨y, and ¬x can be expressed by tabulating their values with truth tables as follows, the first operation, x → y, or Cxy, is called material implication. If x is then the value of x → y is taken to be that of y
17.
Mathematics
–
Mathematics is the study of topics such as quantity, structure, space, and change. There is a range of views among mathematicians and philosophers as to the exact scope, Mathematicians seek out patterns and use them to formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proof, when mathematical structures are good models of real phenomena, then mathematical reasoning can provide insight or predictions about nature. Through the use of abstraction and logic, mathematics developed from counting, calculation, measurement, practical mathematics has been a human activity from as far back as written records exist. The research required to solve mathematical problems can take years or even centuries of sustained inquiry, rigorous arguments first appeared in Greek mathematics, most notably in Euclids Elements. Galileo Galilei said, The universe cannot be read until we have learned the language and it is written in mathematical language, and the letters are triangles, circles and other geometrical figures, without which means it is humanly impossible to comprehend a single word. Without these, one is wandering about in a dark labyrinth, carl Friedrich Gauss referred to mathematics as the Queen of the Sciences. Benjamin Peirce called mathematics the science that draws necessary conclusions, David Hilbert said of mathematics, We are not speaking here of arbitrariness in any sense. Mathematics is not like a game whose tasks are determined by arbitrarily stipulated rules, rather, it is a conceptual system possessing internal necessity that can only be so and by no means otherwise. Albert Einstein stated that as far as the laws of mathematics refer to reality, they are not certain, Mathematics is essential in many fields, including natural science, engineering, medicine, finance and the social sciences. Applied mathematics has led to entirely new mathematical disciplines, such as statistics, Mathematicians also engage in pure mathematics, or mathematics for its own sake, without having any application in mind. There is no clear line separating pure and applied mathematics, the history of mathematics can be seen as an ever-increasing series of abstractions. The earliest uses of mathematics were in trading, land measurement, painting and weaving patterns, in Babylonian mathematics elementary arithmetic first appears in the archaeological record. Numeracy pre-dated writing and numeral systems have many and diverse. Between 600 and 300 BC the Ancient Greeks began a study of mathematics in its own right with Greek mathematics. Mathematics has since been extended, and there has been a fruitful interaction between mathematics and science, to the benefit of both. Mathematical discoveries continue to be made today, the overwhelming majority of works in this ocean contain new mathematical theorems and their proofs. The word máthēma is derived from μανθάνω, while the modern Greek equivalent is μαθαίνω, in Greece, the word for mathematics came to have the narrower and more technical meaning mathematical study even in Classical times
18.
Multiplexer
–
In electronics, a multiplexer is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n lines, which are used to select which input line to send to the output. Multiplexers are mainly used to increase the amount of data that can be sent over the network within a certain amount of time, a multiplexer is also called a data selector. Multiplexers can also be used to implement Boolean functions of multiple variables, conversely, a demultiplexer is a device taking a single input signal and selecting one of many data-output-lines, which is connected to the single input. A multiplexer is often used with a complementary demultiplexer on the receiving end, an electronic multiplexer can be considered as a multiple-input, single-output switch, and a demultiplexer as a single-input, multiple-output switch. The schematic symbol for a multiplexer is a trapezoid with the longer parallel side containing the input pins. The schematic on the shows a 2-to-1 multiplexer on the left. The s e l wire connects the desired input to the output, one use for multiplexers is economizing connections over a single channel, by connecting the multiplexers single output to the demultiplexers single input. The image to the right demonstrates this benefit, in this case, the cost of implementing separate channels for each data source is higher than the cost and inconvenience of providing the multiplexing/demultiplexing functions. At the receiving end of the data link a complementary demultiplexer is usually required to break the data stream back down into the original streams. In some cases, the far end system may have functionality greater than a simple demultiplexer, often, a multiplexer and demultiplexer are combined together into a single piece of equipment, which is conveniently referred to as a multiplexer. Both circuit elements are needed at both ends of a transmission link because most communications systems transmit in both directions, in analog circuit design, a multiplexer is a special type of analog switch that connects one signal selected from several inputs to a single output. In digital circuit design, the wires are of digital value. In the case of a 2-to-1 multiplexer, a value of 0 would connect I0 to the output while a logic value of 1 would connect I1 to the output. In larger multiplexers, the number of pins is equal to ⌈ log 2 ⌉ where n is the number of inputs. For example,9 to 16 inputs would require no fewer than 4 selector pins and 17 to 32 inputs would require no fewer than 5 selector pins, the binary value expressed on these selector pins determines the selected input pin. A straightforward realization of this 2-to-1 multiplexer would need 2 AND gates, an OR gate, while this is mathematically correct, it should be noted that a direct physical implementation would be prone to race conditions that require additional gates to suppress. Larger multiplexers are also common and, as stated above, require ⌈ log 2 ⌉ selector pins for n inputs, other common sizes are 4-to-1, 8-to-1, and 16-to-1
19.
Arithmetic logic unit
–
An arithmetic logic unit is a combinational digital electronic circuit that performs arithmetic and bitwise operations on integer binary numbers. This is in contrast to a floating-point unit, which operates on floating point numbers, an ALU is a fundamental building block of many types of computing circuits, including the central processing unit of computers, FPUs, and graphics processing units. A single CPU, FPU or GPU may contain multiple ALUs, in many designs, the ALU also exchanges additional information with a status register, which relates to the result of the current or previous operations. An ALU has a variety of input and output nets, which are the electrical conductors used to digital signals between the ALU and external circuitry. When an ALU is operating, external circuits apply signals to the ALU inputs and, in response, a basic ALU has three parallel data buses consisting of two input operands and a result output. Each data bus is a group of signals that conveys one binary integer number, typically, the A, B and Y bus widths are identical and match the native word size of the external circuitry. The opcode size is related to the number of different operations the ALU can perform, for example, a four-bit opcode can specify up to sixteen different ALU operations. Generally, an ALU opcode is not the same as a machine language opcode, the status outputs are various individual signals that convey supplemental information about the result of an ALU operation. These outputs are usually stored in registers so they can be used in future ALU operations or for controlling conditional branching. The collection of bit registers that store the status outputs are often treated as a single, multi-bit register, zero, which indicates all bits of output are logic zero. Negative, which indicates the result of an operation is negative. Overflow, which indicates the result of an operation has exceeded the numeric range of output. Parity, which indicates whether an even or odd number of bits in the output are logic one, the status input allows additional information to be made available to the ALU when performing an operation. Typically, this is a bit that is the stored carry-out from a previous ALU operation. An ALU is a logic circuit, meaning that its outputs will change asynchronously in response to input changes. In general, external circuitry controls an ALU by applying signals to its inputs, at the same time, the CPU also routes the ALU result output to a destination register that will receive the sum. The ALUs input signals, which are stable until the next clock, are allowed to propagate through the ALU. When the next clock arrives, the destination register stores the ALU result and, since the ALU operation has completed, a number of basic arithmetic and bitwise logic functions are commonly supported by ALUs
20.
Computer memory
–
In computing, memory refers to the computer hardware devices involved to store information for immediate use in a computer, it is synonymous with the term primary storage. Computer memory operates at a speed, for example random-access memory, as a distinction from storage that provides slow-to-access program and data storage. If needed, contents of the memory can be transferred to secondary storage. An archaic synonym for memory is store, there are two main kinds of semiconductor memory, volatile and non-volatile. Examples of non-volatile memory are flash memory and ROM, PROM, EPROM and EEPROM memory, most semiconductor memory is organized into memory cells or bistable flip-flops, each storing one bit. Flash memory organization includes both one bit per cell and multiple bits per cell. The memory cells are grouped into words of fixed word length, each word can be accessed by a binary address of N bit, making it possible to store 2 raised by N words in the memory. This implies that processor registers normally are not considered as memory, since they only store one word, typical secondary storage devices are hard disk drives and solid-state drives. In the early 1940s, memory technology oftenly permit a capacity of a few bytes, the next significant advance in computer memory came with acoustic delay line memory, developed by J. Presper Eckert in the early 1940s. Delay line memory would be limited to a capacity of up to a few hundred thousand bits to remain efficient, two alternatives to the delay line, the Williams tube and Selectron tube, originated in 1946, both using electron beams in glass tubes as means of storage. Using cathode ray tubes, Fred Williams would invent the Williams tube, the Williams tube would prove more capacious than the Selectron tube and less expensive. The Williams tube would prove to be frustratingly sensitive to environmental disturbances. Efforts began in the late 1940s to find non-volatile memory, jay Forrester, Jan A. Rajchman and An Wang developed magnetic core memory, which allowed for recall of memory after power loss. Magnetic core memory would become the dominant form of memory until the development of transistor-based memory in the late 1960s, developments in technology and economies of scale have made possible so-called Very Large Memory computers. The term memory when used with reference to computers generally refers to Random Access Memory or RAM, volatile memory is computer memory that requires power to maintain the stored information. Most modern semiconductor volatile memory is either static RAM or dynamic RAM, SRAM retains its contents as long as the power is connected and is easy for interfacing, but uses six transistors per bit. SRAM is not worthwhile for desktop system memory, where DRAM dominates, SRAM is commonplace in small embedded systems, which might only need tens of kilobytes or less. Forthcoming volatile memory technologies that aim at replacing or competing with SRAM and DRAM include Z-RAM and A-RAM, non-volatile memory is computer memory that can retain the stored information even when not powered