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96-442: The Sinclair Sovereign was a high-end calculator introduced by Clive Sinclair 's company Sinclair Radionics in 1976. It was an attempt to escape from the unprofitable low end of the market, and one of the last calculators Sinclair produced. Made with a case of pressed steel that a variety of finishes, it cost between £30 and £60 at a time when other calculators could be purchased for under £5 . A number of factors meant that

192-554: A Design Council award, and there are examples of the Sovereign in the Museum of Modern Art in New York . It had a Mostek MK50321N main integrated circuit and a small memory register , a LED display, and could perform a variety of a number of basic mathematical operations besides four-function arithmetic. The Sovereign was one of the last calculators produced during Sinclair's foray into

288-427: A barrel is worn and needs to be replaced. The end of the chamber, freebore and leade (the unrifled portion of the barrel just forward of the chamber), as well as the first few centimeters or few inches of rifling, in rifles are subject to very high temperatures—as the energy content of rifle propellants can exceed 3500 kJ/kg—and pressures that can exceed 380 MPa (55,114 psi). The propellant gases act similarly as

384-475: A bath surface tension less than 35 dyn/cm is necessary to prevent plating solution from becoming airborne when bubbles rise to the surface and pop. This requires a frequent cycle of treating the bath with a wetting agent fume suppressant and confirming the effect on surface tension. Usually, surface tension is measured with a stalagmometer or tensiometer . This method is, however, tedious and suffers from inaccuracy (errors up to 22 dyn/cm have been reported), and

480-552: A broader set of conditions (such as oxidation resistance), and bulking material for worn parts to restore their original dimensions. It is very hard, measuring between 65 and 69 HRC (also based on the base metal's hardness). Hard chrome tends to be thicker than decorative chrome, with standard thicknesses in non-salvage applications ranging from 20 to 40 μm, but it can be an order of magnitude thicker for extreme wear resistance requirements, in such cases 100 μm or thicker provides optimal results. Unfortunately, such thicknesses emphasize

576-407: A button can perform multi-function working with key combinations . Calculators usually have liquid-crystal displays (LCD) as output in place of historical light-emitting diode (LED) displays and vacuum fluorescent displays (VFD); details are provided in the section Technical improvements . Large-sized figures are often used to improve readability; while using decimal separator (usually

672-399: A calculator could be made using just a few chips of low power consumption, allowing portable models powered from rechargeable batteries. The first handheld calculator was a 1967 prototype called Cal Tech , whose development was led by Jack Kilby at Texas Instruments in a research project to produce a portable calculator. It could add, multiply, subtract, and divide, and its output device

768-593: A complementary color. In the last years of the Korean War , the US contemplated banning chrome in favor of several cheaper processes (such as plating with zinc and then coating with shiny plastic). In 2007, a Restriction of Hazardous Substances Directive (RoHS) was issued banning several toxic substances for use in the automotive industry in Europe, including hexavalent chromium , which is used in chrome plating. However, chrome plating

864-669: A development from the "Cal-Tech" project. It had no traditional display; numerical output was on thermal paper tape. Sharp put in great efforts in size and power reduction and introduced in January 1971 the Sharp EL-8 , also marketed as the Facit 1111, which was close to being a pocket calculator. It weighed 1.59 pounds (721 grams), had a vacuum fluorescent display , rechargeable NiCad batteries, and initially sold for US$ 395. However, integrated circuit development efforts culminated in early 1971 with

960-588: A full single chip calculator IC for the Monroe Royal Digital III calculator. Pico was a spinout by five GI design engineers whose vision was to create single chip calculator ICs. Pico and GI went on to have significant success in the burgeoning handheld calculator market. The first truly pocket-sized electronic calculator was the Busicom LE-120A "HANDY", which was marketed early in 1971. Made in Japan, this

1056-424: A part typically includes some or all of these steps: There are many variations to this process, depending on the type of substrate being plated. Different substrates need different etching solutions, such as hydrochloric , hydrofluoric , and sulfuric acids . Ferric chloride is also popular for the etching of nimonic alloys. Sometimes the component enters the chrome plating vat while electrically live. Sometimes

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1152-485: A pocket calculator. Launched in early 1972, it was unlike the other basic four-function pocket calculators then available in that it was the first pocket calculator with scientific functions that could replace a slide rule . The $ 395 HP-35 , along with nearly all later HP engineering calculators, uses reverse Polish notation (RPN), also called postfix notation. A calculation like "8 plus 5" is, using RPN, performed by pressing 8 , Enter↑ , 5 , and + ; instead of

1248-428: A point rather than a comma ) instead of or in addition to vulgar fractions . Various symbols for function commands may also be shown on the display. Fractions such as 1 ⁄ 3 are displayed as decimal approximations , for example rounded to 0.33333333 . Also, some fractions (such as 1 ⁄ 7 , which is 0.14285714285714 ; to 14 significant figures ) can be difficult to recognize in decimal form; as

1344-437: A result, many scientific calculators are able to work in vulgar fractions or mixed numbers . Calculators also have the ability to save numbers into computer memory . Basic calculators usually store only one number at a time; more specific types are able to store many numbers represented in variables . Usually these variables are named ans or ans(0). The variables can also be used for constructing formulas . Some models have

1440-420: A series of separate identical seven-segment displays to build a metering circuit, for example. If the numeric quantity were stored and manipulated as pure binary, interfacing to such a display would require complex circuitry. Therefore, in cases where the calculations are relatively simple, working throughout with BCD can lead to a simpler overall system than converting to and from binary. (For example, CDs keep

1536-414: A toxic mist of water and hexavalent chromium is released from the bath. Wet scrubbers are used to control these emissions. The liquid from the wet scrubbers is treated to precipitate the chromium and remove it from the wastewater before it is discharged. Additional toxic waste created from hexavalent chromium baths include lead chromates , which form in the bath because lead anodes are used. Barium

1632-403: Is hydrogen evolution reaction (HER), and the role of chromate is to scavenge H ions in a reaction that competes with H 2 evolution: The shine of plated chrome depends on whether microscopic cracks in the plating are visible on the surface. The dull appearance of some chrome layers is due to continuous cracks that propagate through the whole plated metal layer, while bright deposits appear in

1728-460: Is also dependent on the current density, because a higher current density requires a higher temperature. Finally, the whole bath is agitated to keep the temperature steady and achieve a uniform deposition. One functional disadvantage of hexavalent chromium plating is low cathode efficiency, which results in bad throwing power . This means it leaves a non-uniform coating, with more on edges and less in inside corners and holes. To overcome this problem

1824-497: Is also used to control the sulfate concentration, which leads to the formation of barium sulfate (BaSO 4 ). Trivalent chromium is intrinsically less toxic than hexavalent chromium. Because of the lower toxicity it is not regulated as strictly, which reduces overhead costs . Other health advantages include higher cathode efficiencies, which lead to less chromium air emissions; lower concentration levels, resulting in less chromium waste and anodes that do not decompose. Maintaining

1920-419: Is common in electronic systems where a numeric value is to be displayed, especially in systems consisting solely of digital logic, and not containing a microprocessor. By employing BCD, the manipulation of numerical data for display can be greatly simplified by treating each digit as a separate single sub-circuit. This matches much more closely the physical reality of display hardware—a designer might choose to use

2016-678: Is dependent on the user's experience and capabilities. While they are effective for the control of toxic airborne chromium, many widely used wetting agent fume suppressants are toxic themselves because they contain perfluoroalkyl substances (PFAS), which are hazardous chemicals that can cause long-term health effects. This makes electroplating one of the jobs with the highest risk of occupational exposure to PFAS, but not as high as firefighters using fluorinated aqueous film forming foams . In addition to their detrimental effects on human health, PFAS are persistent pollutants that cause significant bioaccumulation and biomagnification , putting animals at

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2112-425: Is designed to be aesthetically pleasing and durable. Thicknesses range from 2 to 20 μin (0.05 to 0.5 μm), however, they are usually between 5 and 10 μin (0.13 and 0.25 μm). The chromium plating is usually applied over bright nickel plating . Typical base materials include steel , aluminium , plastic , copper alloys, and zinc alloys. Decorative chrome plating is also very corrosion resistant and

2208-563: Is done from liquids comprising Cr species. Such solutions were avoided prior to ca. 2020, because of air-sensitivity and hydrogen evolution from aqueous Cr solutions. In the 2020s, it was discovered that chromous chloride has ca. 4.0 M solubility in water at room temperature (i.e. with H 2 O:Cr molar ratio around 14:1), and such liquids behave like supersaturated electrolytes with a reduced propensity toward hydrogen evolution. The best quality bright deposits are produced at relatively high current density of 20 mA/cm . Decorative chrome

2304-472: Is metal and contains no hexavalent chromium after it is rinsed, so chrome plating is not banned. Chrome-lining protects the barrel or chamber of arms from corrosion and makes these parts also easier to clean, but this is not the main purpose for lining a barrel or chamber. Chrome-lining was introduced in machine guns to increase the wear resistance and service life of highly stressed arms parts like barrels and chambers, allowing more rounds to be fired before

2400-413: Is more robust than hexavalent chromium because it can withstand current interruptions. One of the disadvantages when the process was first introduced was that decorative customers disapproved of the color differences. Companies now use additives to adjust the color. In hard coating applications, the corrosion resistance of thicker coatings is not quite as good as it is with hexavalent chromium. The cost of

2496-467: Is needed to fit all the desired functions in the limited memory space available in the calculator chip , with acceptable calculation time. The first known tools used to aid arithmetic calculations were: bones (used to tally items), pebbles, and counting boards , and the abacus , known to have been used by Sumerians and Egyptians before 2000 BC. Except for the Antikythera mechanism (an "out of

2592-405: Is notably different from the layout of telephone Touch-Tone keypads which have the 1 - 2 - 3 keys on top and 7 - 8 - 9 keys on the third row. In general, a basic electronic calculator consists of the following components: Clock rate of a processor chip refers to the frequency at which the central processing unit (CPU) is running. It is used as an indicator of

2688-415: Is often used on car parts, tools and kitchen utensils. Thin dense chrome (TDC) differs from decorative chrome. While decorative chrome is applied primarily for aesthetic purposes with thin layers that provide a shiny finish, TDC, such as Armoloy , focuses on enhancing surface performance. It delivers wear resistance, corrosion protection, and hardness without adding significant thickness. TDC also avoids

2784-533: Is subject to different types of quality requirements depending on the application; for instance, the plating on hydraulic piston rods are tested for corrosion resistance with a salt spray test . Most bright decorative items affixed to cars are referred to as "chrome", meaning steel that has undergone several plating processes to protect it from weathering and moisture but the term passed on to cover any similar-looking shiny decorative auto parts, including silver plastic trim pieces in casual terminology. Triple plating

2880-598: Is the first calculator in the world which includes the square root function. Later that same year were released the ELKA 22 (with a luminescent display) and the ELKA 25, with an built-in printer. Several other models were developed until the first pocket model, the ELKA 101 , was released in 1974. The writing on it was in Roman script , and it was exported to western countries. The first desktop programmable calculators were produced in

2976-418: Is the most expensive and durable process, which involves plating the steel first with copper and then nickel before the chromium plating is applied. Prior to the application of chrome in the 1920s, nickel electroplating was used. In the short production run prior to the US entry into World War II , the government banned plating to save chromium and automobile manufacturers painted the decorative pieces in

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3072-730: Is wasted when grinding the piece back to desired dimensions. Modern engineered coatings do not suffer such drawbacks, which often price hard chrome out due to labor costs alone. Hard chrome replacement technologies outperform hard chrome in wear resistance, corrosion resistance, and cost. Hardness up to 80 HRC is not extraordinary for such materials. Modern engineered coatings applied using spray deposition can form layers of uniform thickness that often require no further polishing or machining. These coatings are often composites of polymers , metals, and ceramic powders or fibers as proprietary formulas protected by patents or as trade secrets, and thus are usually known by brand names. Hard chromium plating

3168-497: The Sinclair Cambridge . Clive Sinclair had assumed that people would prefer attractive illuminated LED displays to LCD displays, which incidentally also required more expensive CMOS chips. However, his calculators were designed with the assumption they would be turned off between calculations, which did not prove to be the case. Advertisements suggested that the batteries would last "about a year" under normal use, but in reality

3264-432: The "active Cr " also undergoes within less than 1 second a transition into "inactive Cr ", which is believed to be a polymeric hexa-aqua complex. Some complexes of Cr with ligand other than water can undergo relatively fast electroreduction to metallic chromium, and they are used in chromate-free chromium plating methods. A different school of thought suggests, that the main problem with chromium plating from Cr solution

3360-538: The 1970s, especially after the Intel 4004 , the first microprocessor , was developed by Intel for the Japanese calculator company Busicom . Modern electronic calculators vary from cheap, give-away, credit-card-sized models to sturdy desktop models with built-in printers. They became popular in the mid-1970s as the incorporation of integrated circuits reduced their size and cost. By the end of that decade, prices had dropped to

3456-507: The ANITA was superseded in June 1963 by the U.S. manufactured Friden EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a 5-inch (13 cm) cathode-ray tube (CRT), and introduced Reverse Polish Notation (RPN) to the calculator market for a price of $ 2200, which was about three times the cost of an electromechanical calculator of the time. Like Bell Punch, Friden

3552-590: The Autumn of 1971, with four functions and an eight-digit red LED display, for US$ 240 , while in August 1972 the four-function Sinclair Executive became the first slimline pocket calculator measuring 5.4 by 2.2 by 0.35 inches (137.2 mm × 55.9 mm × 8.9 mm) and weighing 2.5 ounces (71 g). It retailed for around £79 ( US$ 194 at the time). By the end of the decade, similar calculators were priced less than £5 ($ 6.85). Following protracted development over

3648-687: The Mk VII for continental Europe and the Mk VIII for Britain and the rest of the world, both for delivery from early 1962. The Mk VII was a slightly earlier design with a more complicated mode of multiplication, and was soon dropped in favour of the simpler Mark VIII. The ANITA had a full keyboard, similar to mechanical comptometers of the time, a feature that was unique to it and the later Sharp CS-10A among electronic calculators. The ANITA weighed roughly 33 pounds (15 kg) due to its large tube system. Bell Punch had been producing key-driven mechanical calculators of

3744-439: The Sovereign was not a commercial success, including the cost, high import levies on components, competition from cheaper calculators manufactured abroad, and the development of more power-efficient designs using liquid-crystal displays . Though it came with a five-year guarantee, issues such as short battery life limited its usefulness. The company moved on to producing computers soon afterwards. The design by John Pemberton won

3840-582: The Sovereign was sold with a "full and unconditional" five year guarantee. The Sovereign came in satin chrome and gold-plated models, with leather pouches and fitted wooden cases. It had an 8-digit seven-segment display that used red light-emitting diodes , with a decimal point to the right of each digit that could be illuminated as necessary. Power was provided by two 1.35 mercury button cells . The Sovereign measured 36 by 141 by 12 millimetres (1.42 in × 5.55 in × 0.47 in), which made it small and sleek compared to other calculators of

3936-493: The ability to extend memory capacity to store more numbers; the extended memory address is termed an array index. Power sources of calculators are batteries , solar cells or mains electricity (for old models), turning on with a switch or button. Some models even have no turn-off button but they provide some way to put off (for example, leaving no operation for a moment, covering solar cell exposure, or closing their lid ). Crank -powered calculators were also common in

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4032-432: The ability to multiply by a fixed constant. With an eight-digit display, the calculator could display positive numbers between 0.0000001 and 99,999,999, and negative numbers between -0.000001 and -9,999,999. Calculators of the time tended to have displays of between 3 and 12 digits, as reducing the number of digits was an effective way of reducing the cost of the calculator. A number outside that range leads to an overflow, and

4128-507: The activation step is done in the chromium bath. The chromium bath is a mixture of chromium trioxide and sulfuric acid , the ratio of which varies greatly between 75:1 to 250:1 by weight. This results in an extremely acidic bath (pH 0). The temperature and current density in the bath affect the brightness and final coverage. For decorative coating the temperature ranges from 35 to 45 °C (100 to 110 °F), but for hard coating it ranges from 50 to 65 °C (120 to 150 °F). Temperature

4224-413: The adding machine as a means of completing this operation. There is a debate about whether Pascal or Shickard should be credited as the known inventor of a calculating machine due to the differences (like the different aims) of both inventions. Schickard and Pascal were followed by Gottfried Leibniz who spent forty years designing a four-operation mechanical calculator, the stepped reckoner , inventing in

4320-552: The algebraic infix notation : 8 , + , 5 , = . It had 35 buttons and was based on Mostek Mk6020 chip. The first Soviet scientific pocket-sized calculator the "B3-18" was completed by the end of 1975. In 1973, Texas Instruments (TI) introduced the SR-10 , ( SR signifying slide rule ) an algebraic entry pocket calculator using scientific notation for $ 150. Shortly after the SR-11 featured an added key for entering pi (π). It

4416-626: The calculator market that had started with the Sinclair Executive in September 1972. The Executive had retailed for £80 when introduced, but in little over a year it was possible to purchase a Sinclair calculator for £20 and by November 1976 a model was available for £4.95 . Cheaper calculators with liquid-crystal displays instead of light-emitting diodes were becoming more popular, and had much longer battery lives of months or years. Such calculators were available for well under £10 , with all

4512-525: The calculator market was due in part to technological development leading to smaller and cheaper components, which put heavy pressure on profit margins. An import levy of up to 17.5% was placed on components, but the duty for calculators imported from Japan or Hong Kong could be as little as 5%, making it unprofitable to produce calculators in the UK. Sinclair also had some problems with the reliability of earlier calculators that had adversely affected its reputation, but

4608-405: The chemicals is greater, but this is usually offset by greater production rates and lower overhead costs. In general, the process must be controlled more closely than in hexavalent chromium plating, especially with respect to metallic impurities. This means processes that are hard to control, such as barrel plating, are much more difficult using a trivalent chromium bath. Divalent chromium plating

4704-442: The component has a conforming anode made from lead/tin or platinized titanium. A typical hard chrome vat plates at about 0.001 inches (25 μm) per hour. Some common industry specifications governing the chrome plating process are AMS 2460, AMS 2406, and MIL-STD-1501. Hexavalent chromium plating , also known as hex-chrome , Cr , and chrome(VI) plating, uses chromium trioxide (CrO 3 , also known as chromic anhydride) as

4800-415: The comptometer type under the names "Plus" and "Sumlock", and had realised in the mid-1950s that the future of calculators lay in electronics. They employed the young graduate Norbert Kitz, who had worked on the early British Pilot ACE computer project, to lead the development. The ANITA sold well since it was the only electronic desktop calculator available, and was silent and quick. The tube technology of

4896-524: The course of two years including a botched partnership with Texas Instruments, Eldorado Electrodata released five pocket calculators in 1972. One called the Touch Magic was "no bigger than a pack of cigarettes" according to Administrative Management . The first Soviet Union made pocket-sized calculator, the Elektronika B3-04 was developed by the end of 1973 and sold at the start of 1974. One of

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4992-428: The early computer era. The following keys are common to most pocket calculators. While the arrangement of the digits is standard, the positions of other keys vary from model to model; the illustration is an example. The arrangement of digits on calculator and other numeric keypads with the 7 - 8 - 9 keys two rows above the 1 - 2 - 3 keys is derived from calculators and cash registers . It

5088-404: The end of the chamber, freebore, leade and rifling. Hard chrome-lining protects the chamber, freebore, leade and rifling with a thin coat of wear resistant chrome. This significantly extends barrel life in arms that are fired for prolonged periods in full-auto or sustained rapid fire modes. Some arms manufacturers use Stellite-lining alloy as an alternative to hard chrome-lining to further increase

5184-493: The eve of the industrial revolution made large scale production of more compact and modern units possible. The Arithmometer , invented in 1820 as a four-operation mechanical calculator, was released to production in 1851 as an adding machine and became the first commercially successful unit; forty years later, by 1890, about 2,500 arithmometers had been sold plus a few hundreds more from two arithmometer clone makers (Burkhardt, Germany, 1878 and Layton, UK, 1883) and Felt and Tarrant,

5280-463: The first Japanese one) was the Casio (AL-1000) produced in 1967. It featured a nixie tubes display and had transistor electronics and ferrite core memory. The Monroe Epic programmable calculator came on the market in 1967. A large, printing, desk-top unit, with an attached floor-standing logic tower, it could be programmed to perform many computer-like functions. However, the only branch instruction

5376-483: The first direct multiplication machine in 1834: this was also the second key-driven machine in the world, following that of James White (1822). It was not until the 19th century and the Industrial Revolution that real developments began to occur. Although machines capable of performing all four arithmetic functions existed prior to the 19th century, the refinement of manufacturing and fabrication processes during

5472-492: The first low-cost calculators was the Sinclair Cambridge , launched in August 1973. It retailed for £29.95 ($ 41.03), or £5 ($ 6.85) less in kit form, and later models included some scientific functions. The Sinclair calculators were successful because they were far cheaper than the competition; however, their design led to slow and less accurate computations of transcendental functions (maximum three decimal places of accuracy). Meanwhile, Hewlett-Packard (HP) had been developing

5568-455: The flame from a cutting torch, the gases heating up the metal to red-hot state and the velocity tearing away metal. Under slow fire conditions, the affected areas are able to cool sufficiently in between shots. Under sustained rapid fire or automatic/cyclic fire there is no time for the heat to dissipate. The heat and pressure effects exerted by the hot propellant gasses and friction by the projectile can quickly cause damage by washing away metal at

5664-481: The functionality of the more expensive models. The impossibility of selling "simple" calculators profitably led Sinclair to introduce models such as the Cambridge Scientific , introduced in August 1975 at a price of £29.95 . The Sovereign, released in 1976, represented an attempt to move upmarket in an increasingly saturated market . In December 1976, the chrome plated version of the Sovereign cost £30 and

5760-565: The gold-plated version £60 , including VAT , but profit margins on the Sovereign were so small that Sinclair ended up selling the Sovereign at a loss, and it was not a commercial success. The Sovereign was made in England, like every other Sinclair calculator except the President . Sinclair would shortly stop producing calculators and instead focus on computers, starting with the MK14 in 1977. The loss of

5856-513: The highest trophic level at the highest risk for toxic effects. It has been known for over a century, that chromium electroplating is relatively easy from (di)chromate solutions, but difficult from Cr solutions. Several theories have been proposed to explain this finding. An earlier view suggested, that an active Cr species (perhaps, with a ligand rather than water) forms initially from electroreduced Cr . This active Cr species can be reduced into metallic chromium relatively easy. However,

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5952-603: The introduction of the first "calculator on a chip", the MK6010 by Mostek , followed by Texas Instruments later in the year. Although these early hand-held calculators were very costly, these advances in electronics, together with developments in display technology (such as the vacuum fluorescent display , LED , and LCD ), led within a few years to the cheap pocket calculator available to all. In 1971, Pico Electronics and General Instrument also introduced their first collaboration in ICs,

6048-582: The limitations of the process, which are overcome by plating extra thickness then grinding down and lapping to meet requirements, or to improve the overall aesthetics of the chromed piece. Increasing plating thickness amplifies surface defects and roughness in proportional severity, because hard chrome does not have a leveling effect. Pieces that are not ideally shaped in reference to electric field geometries (nearly every piece sent in for plating, except spheres and egg shaped objects) require even thicker plating to compensate for non-uniform deposition, and much of it

6144-547: The logic circuits, appeared in the 1940s and 1950s. Electronic circuits developed for computers also had application to electronic calculators. The Casio Computer Company, in Japan , released the Model 14-A calculator in 1957, which was the world's first all-electric (relatively) compact calculator. It did not use electronic logic but was based on relay technology, and was built into a desk. The IBM 608 plugboard programmable calculator

6240-433: The main ingredient. Hexavalent chromium plating solution is used for both decorative and hard plating, as well as bright dipping of copper alloys, chromic acid anodizing , and chromate conversion coating . A typical hexavalent chromium plating process is: The activation bath is typically a tank of chromic acid with a reverse current run through it. This etches the work-piece surface and removes any scale . In some cases,

6336-425: The main ingredient. Trivalent chromium plating is an alternative to hexavalent chromium in certain applications and thicknesses (e.g. decorative plating). A trivalent chromium plating process is similar to the hexavalent chromium plating process, except for the bath chemistry and anode composition. There are three main types of trivalent chromium bath configurations: The trivalent chromium-plating process can plate

6432-530: The microcracking associated with decorative chrome, making it ideal for industrial applications where durability and friction reduction are necessary. Thin dense chrome is commonly used in precision tools, aerospace, medical, and food processing equipment. Hard chrome , also known as industrial chrome or engineered chrome , is used to reduce friction, improve durability through abrasion tolerance and wear resistance in general, minimize galling or seizing of parts, expand chemical inertness to include

6528-619: The mid-1960s. They included the Mathatronics Mathatron (1964) and the Olivetti Programma 101 (late 1965) which were solid-state, desktop, printing, floating point, algebraic entry, programmable, stored-program electronic calculators. Both could be programmed by the end user and print out their results. The Programma 101 saw much wider distribution and had the added feature of offline storage of programs via magnetic cards. Another early programmable desktop calculator (and maybe

6624-695: The only other competitor in true commercial production, had sold 100 comptometers . It wasn't until 1902 that the familiar push-button user interface was developed, with the introduction of the Dalton Adding Machine, developed by James L. Dalton in the United States . In 1921, Edith Clarke invented the "Clarke calculator", a simple graph-based calculator for solving line equations involving hyperbolic functions. This allowed electrical engineers to simplify calculations for inductance and capacitance in power transmission lines . The Curta calculator

6720-428: The part may be over-plated and ground to size, or auxiliary anodes may be used around the hard-to-plate areas. Hexavalent chromium is also considerably more toxic than trivalent chromium, rendering it a major health risk both in manufacturing and disposal if not handled with care. Trivalent chromium plating , also known as tri-chrome , Cr , and chrome(III) plating, uses chromium sulfate or chromium chloride as

6816-426: The point where a basic calculator was affordable to most and they became common in schools. In addition to general purpose calculators, there are those designed for specific markets. For example, there are scientific calculators , which include trigonometric and statistical calculations. Some calculators even have the ability to do computer algebra . Graphing calculators can be used to graph functions defined on

6912-422: The power grid, was released at the start of the 1970s. The electronic calculators of the mid-1960s were large and heavy desktop machines due to their use of hundreds of transistors on several circuit boards with a large power consumption that required an AC power supply. There were great efforts to put the logic required for a calculator into fewer and fewer integrated circuits (chips) and calculator electronics

7008-421: The process his leibniz wheel , but who couldn't design a fully operational machine. There were also five unsuccessful attempts to design a calculating clock in the 17th century. The 18th century saw the arrival of some notable improvements, first by Poleni with the first fully functional calculating clock and four-operation machine, but these machines were almost always one of a kind . Luigi Torchi invented

7104-631: The processor's speed, and is measured in clock cycles per second or hertz (Hz) . For basic calculators, the speed can vary from a few hundred hertz to the kilohertz range. A basic explanation as to how calculations are performed in a simple four-function calculator: To perform the calculation 25 + 9 , one presses keys in the following sequence on most calculators: 2   5   +   9   = . Other functions are usually performed using repeated additions or subtractions. Most pocket calculators do all their calculations in binary-coded decimal (BCD) rather than binary. BCD

7200-508: The real line, or higher-dimensional Euclidean space . As of 2016 , basic calculators cost little, but scientific and graphing models tend to cost more. Computer operating systems as far back as early Unix have included interactive calculator programs such as dc and hoc , and interactive BASIC could be used to do calculations on most 1970s and 1980s home computers. Calculator functions are included in most smartphones , tablets , and personal digital assistant (PDA) type devices. With

7296-603: The same time). The Victor 3900 was the first to use integrated circuits in place of individual transistors , but production problems delayed sales until 1966. There followed a series of electronic calculator models from these and other manufacturers, including Canon , Mathatronics , Olivetti , SCM (Smith-Corona-Marchant), Sony , Toshiba , and Wang . The early calculators used hundreds of germanium transistors , which were cheaper than silicon transistors , on multiple circuit boards. Display types used were CRT, cold-cathode Nixie tubes , and filament lamps . Memory technology

7392-494: The screen flashes and all keys except the clear key are rendered inoperable to inform the user of the error. An independent memory register could read information from the screen, and information could only be taken from the memory onto the screen. Five keys were used for memory operations. The Sovereign used a Mostek MK50321N main integrated circuit , the same as the Sinclair Wrist Calculator and some variants of

7488-433: The small button cell batteries and comparatively high power consumption meant a short battery life compared to the competition. Calculator An electronic calculator is typically a portable electronic device used to perform calculations , ranging from basic arithmetic to complex mathematics . The first solid-state electronic calculator was created in the early 1960s. Pocket-sized devices became available in

7584-403: The time" astronomical device), development of computing tools arrived near the start of the 17th century: the geometric-military compass (by Galileo ), logarithms and Napier bones (by Napier ), and the slide rule (by Edmund Gunter ). The Renaissance saw the invention of the mechanical calculator by Wilhelm Schickard in 1623, and later by Blaise Pascal in 1642. A device that

7680-514: The time. The Sovereign was unusual because the casing was made from pressed steel , which gave it a much higher quality feel compared to injection moulded plastic. This allowed a variety of paint and plating options, including black painted, chrome-plated , silver-plated, and gold-plated, and a limited edition silver-plated version, inscribed to commemorate the Silver Jubilee of Queen Elizabeth II in 1977, were also produced. Asprey of London

7776-735: The track number in BCD, limiting them to 99 tracks.) The same argument applies when hardware of this type uses an embedded microcontroller or other small processor. Often, smaller code results when representing numbers internally in BCD format, since a conversion from or to binary representation can be expensive on such limited processors. For these applications, some small processors feature BCD arithmetic modes, which assist when writing routines that manipulate BCD quantities. Where calculators have added functions (such as square root, or trigonometric functions ), software algorithms are required to produce high precision results. Sometimes significant design effort

7872-643: The very wide availability of smartphones and the like, dedicated hardware calculators, while still widely used, are less common than they once were. In 1986, calculators still represented an estimated 41% of the world's general-purpose hardware capacity to compute information. By 2007, this had diminished to less than 0.05%. Electronic calculators contain a keyboard with buttons for digits and arithmetical operations; some even contain "00" and "000" buttons to make larger or smaller numbers easier to enter. Most basic calculators assign only one digit or operation on each button; however, in more specific calculators,

7968-694: The wear resistance and service life of highly stressed arms parts. Hexavalent chromium is the most toxic form of chromium. In the U.S., the Environmental Protection Agency regulates it heavily. The EPA lists hexavalent chromium as a hazardous air pollutant because it is a human carcinogen , a "priority pollutant" under the Clean Water Act , and a "hazardous constituent" under the Resource Conservation and Recovery Act . Due to its low cathodic efficiency and high solution viscosity ,

8064-412: The workpieces at a similar temperature, rate and hardness, as compared to hexavalent chromium. Plating thickness ranges from 5 to 50 μin (0.13 to 1.27 μm). The functional advantages of trivalent chromium are higher cathode efficiency and better throwing power. Better throwing power means better production rates. Less energy is required because of the lower current densities required. The process

8160-616: Was IBM's first all-transistor product, released in 1957; this was a console type system, with input and output on punched cards, and replaced the earlier, larger, vacuum-tube IBM 603 . In October 1961, the world's first all-electronic desktop calculator, the British Bell Punch /Sumlock Comptometer ANITA ( A N ew I nspiration T o A rithmetic/ A ccounting) was announced. This machine used vacuum tubes , cold-cathode tubes and Dekatrons in its circuits, with 12 cold-cathode "Nixie" tubes for its display. Two models were displayed,

8256-571: Was a manufacturer of mechanical calculators that had decided that the future lay in electronics. In 1964 more all-transistor electronic calculators were introduced: Sharp introduced the CS-10A , which weighed 25 kilograms (55 lb) and cost 500,000 yen ($ 4555.81), and Industria Macchine Elettroniche of Italy introduced the IME 84, to which several extra keyboard and display units could be connected so that several people could make use of it (but apparently not at

8352-568: Was a paper tape. As a result of the "Cal-Tech" project, Texas Instruments was granted master patents on portable calculators. The first commercially produced portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the Sanyo ICC-0081 "Mini Calculator", the Canon Pocketronic, and the Sharp QT-8B "micro Compet". The Canon Pocketronic was

8448-541: Was also the first calculator to use an LED display, the first hand-held calculator to use a single integrated circuit (then proclaimed as a "calculator on a chip"), the Mostek MK6010, and the first electronic calculator to run off replaceable batteries. Using four AA-size cells the LE-120A measures 4.9 by 2.8 by 0.9 inches (124 mm × 71 mm × 23 mm). The first European-made pocket-sized calculator, DB 800

8544-419: Was an implied unconditional branch (GOTO) at the end of the operation stack, returning the program to its starting instruction. Thus, it was not possible to include any conditional branch (IF-THEN-ELSE) logic. During this era, the absence of the conditional branch was sometimes used to distinguish a programmable calculator from a computer. The first Soviet programmable desktop calculator ISKRA 123 , powered by

8640-436: Was at times somewhat over-promoted as being able to perform all four arithmetic operations with minimal human intervention. Pascal's calculator could add and subtract two numbers directly and thus, if the tedium could be borne, multiply and divide by repetition. Schickard's machine, constructed several decades earlier, used a clever set of mechanised multiplication tables to ease the process of multiplication and division with

8736-470: Was developed in 1948 and, although costly, became popular for its portability. This purely mechanical hand-held device could do addition, subtraction, multiplication and division. By the early 1970s electronic pocket calculators ended manufacture of mechanical calculators, although the Curta remains a popular collectable item. The first mainframe computers, initially using vacuum tubes and later transistors in

8832-589: Was followed the next year by the SR-50 which added log and trig functions to compete with the HP-35, and in 1977 the mass-marketed TI-30 line which is still produced. Chrome-plated Chromium compounds used in electroplating are toxic . In most countries, their disposal is tightly regulated. Some fume suppressants used to control the emission of airborne chromium from plating baths are also toxic, making disposal even more difficult. The preparation and chrome plating of

8928-581: Was made in May 1971 by Digitron in Buje , Croatia (former Yugoslavia ) with four functions and an eight-digit display and special characters for a negative number and a warning that the calculation has too many digits to display. The first American-made pocket-sized calculator, the Bowmar 901B (popularly termed The Bowmar Brain ), measuring 5.2 by 3.0 by 1.5 inches (132 mm × 76 mm × 38 mm), came out in

9024-608: Was one of the leading edges of semiconductor development. U.S. semiconductor manufacturers led the world in large scale integration (LSI) semiconductor development, squeezing more and more functions into individual integrated circuits. This led to alliances between Japanese calculator manufacturers and U.S. semiconductor companies: Canon Inc. with Texas Instruments , Hayakawa Electric (later renamed Sharp Corporation ) with North-American Rockwell Microelectronics (later renamed Rockwell International ), Busicom with Mostek and Intel , and General Instrument with Sanyo . By 1970,

9120-576: Was rumoured to have produced two Sovereigns in solid gold, costing £2,750 each. The design, by John Pemberton, won the Design Council Award in 1977, as the Executive had in 1973, and there are examples in the collection of the Museum of Modern Art in New York . Sovereigns are highly collectible, and used models command high prices. As well as addition, subtraction, multiplication and division, it had reciprocal and square-root functions , and

9216-744: Was usually based on the delay-line memory or the magnetic-core memory , though the Toshiba "Toscal" BC-1411 appears to have used an early form of dynamic RAM built from discrete components. Already there was a desire for smaller and less power-hungry machines. Bulgaria's ELKA 6521 , introduced in 1965, was developed by the Central Institute for Calculation Technologies and built at the Elektronika factory in Sofia . The name derives from EL ektronen KA lkulator , and it weighed around 8 kg (18 lb). It

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