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Focal (HP-41)
The HP-41C series are programmable, expandable, continuous memory handheld RPN calculators made by Hewlett-Packard from 1979 to 1990. The original model, HP-41C, was the first of its kind to offer alphanumeric display capabilities. Later came the HP-41CV and HP-41CX, offering more memory and functionality. The alphanumeric "revolution" The alphanumeric LCD screen of the HP-41C revolutionized the way a pocket calculator could be used, providing user friendliness (for its time) and expandability (keyboard-unassigned functions could be spelled out alphabetically). By using an alphanumeric display, the calculator could tell the user what was going on: it could display error messages, such as showing ("DATA ERROR") upon attempting to divide by zero instead of simply displaying a blinking zero; it could also specifically prompt the user for arguments ("ENTER RADIUS") instead of just displaying a question mark. Earlier calculators needed a key, or key combination, for every ava ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programmable Calculator
Programmable calculators are calculators that can automatically carry out a sequence of operations under control of a stored computer programming, program. Most are Turing complete, and, as such, are theoretically general-purpose computers. However, their user interfaces and programming environments are specifically tailored to make performing small-scale numerical computations convenient, rather than general-purpose use. The first programmable calculators such as the IBM CPC used punched cards or other media for program storage. Hand-held electronic calculators store programs on magnetic strips, removable read-only memory cartridges, flash memory, or in battery-backed read/write memory. Since the early 1990s, most of these flexible handheld units belong to the class of graphing calculators. Before the mass-manufacture of inexpensive dot-matrix LCDs, however, programmable calculators usually featured a one-line numeric or alphanumeric display. The Big Four manufacturers of pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LCD Display Of HP41CX (cropped)
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but instead use a backlight or reflector to produce images in color or monochrome. LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images with low information content, which can be displayed or hidden. For instance: preset words, digits, and seven-segment displays, as in a digital clock, are all good examples of devices with these displays. They use the same basic technology, except that arbitrary images are made from a matrix of small pixels, while other displays have larger elements. LCDs can either be normally on (positive) or off (negative), depending on the polarizer arrangement. For example, a character positive LCD with a backlight will have black lettering on a background that is the colo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embedded System
An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as part of a complete device often including electrical or electronic hardware and mechanical parts. Because an embedded system typically controls physical operations of the machine that it is embedded within, it often has real-time computing constraints. Embedded systems control many devices in common use today. , it was estimated that ninety-eight percent of all microprocessors manufactured were used in embedded systems. Modern embedded systems are often based on microcontrollers (i.e. microprocessors with integrated memory and peripheral interfaces), but ordinary microprocessors (using external chips for memory and peripheral interface circuits) are also common, especially in more complex systems. In either case, the processor(s) used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dot Matrix
A dot matrix is a 2-dimensional patterned array, used to represent characters, symbols and images. Most types of modern technology use dot matrices for display of information, including mobile phones, televisions, and printers. The system is also used in textiles with sewing, knitting and weaving. An alternate form of information display using lines and curves is known as a vector display, was used with early computing devices such as air traffic control radar displays and pen-based plotters but is no longer used. Electronic vector displays were typically monochrome only, and either leave the interiors of closed vector shapes unfilled, or perform slow, time-consuming and often non-uniform shape-filling, as on pen-based plotters. In printers, the dots are usually the darkened areas of the paper. In displays, the dots may light up, as in an LED, CRT, or plasma display, or darken, as in an LCD. Usage in computers Although the output of modern computers is generally all in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sharp PC-1211
The Sharp PC-1211 is a pocket computer marketed by Sharp Corporation in the 1980s. The computer was powered by two 4-bit CPUs laid out in power-saving CMOS circuitry. One acted as the main CPU, the other dealt with the input/output and display interface. Users could write computer programs in BASIC. A badge-engineered version of the PC-1211 was marketed by Radio Shack as the first iteration of the TRS-80 Pocket Computer with just a marginally different look (outer plastic parts in black, not brown, gray display frame) Technical specifications *24 digit dot matrix LCD *Full QWERTY-style keyboard *Integrated beeper *Connector for printer and tape drive *Programmable in BASIC *Uses four MR44 Mercury button cells *Battery life in excess of 200 hours *1424 program steps, 26 permanent variable locations (- or -) and 178 variables shared with program steps *Built out of off-the-shelf CMOS components, including SC43177/SC43178 processors at and three TC5514P RAM modules Accessories ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sharp Electronics
is a Japanese multinational corporation that designs and manufactures electronic products, headquartered in Sakai-ku, Sakai, Osaka Prefecture. Since 2016 it has been majority owned by the Taiwan-based Foxconn Group. Sharp employs more than 50,000 people worldwide. The company was founded in September 1912 in Tokyo and takes its name from one of its founder's first Ever-Sharp mechanical pencil, which was invented by Tokuji Hayakawa in 1915. History Early years 1912–1945 In 1912, Tokuji Hayakawa founded a metal workshop in Tokyo. The first of his many inventions was a snap buckle named 'Tokubijo'. Another of his inventions was the Ever-Ready Sharp mechanical pencil in 1915. The product became one of the first internationally available mechanical pencils (while concurrent US design replaced it soon and became a modern type), and due to this big success the Sharp Corporation derived its name from it. After the pencil business was destroyed by the 1923 Great Kantō earthquake, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FOCAL Character Set
In computing FOCAL character set refers to a group of 8-bit Single Byte Character Set, single byte character sets introduced by Hewlett-Packard since 1979. It was used in several Reverse Polish Notation, RPN HP calculator, calculators supporting the HP FOCAL, FOCAL programming language, like the HP-41C/HP-41CV, CV/HP-41CX, CX as well as the later HP-42S, which was introduced in 1988 and produced up to 1995. As such, it is also used by SwissMicros' SwissMicros DM41, DM41/SwissMicros DM41L, L, both introduced in 2015, and is implicitly supported by the SwissMicros DM42, DM42, introduced in 2017 (although the later calculator utilizes Free42, which is based on Unicode internally). Character set The character set is derived from ASCII, but with the control code range and some high bit characters replaced by various special characters. When Hewlett-Packard introduced the HP-42S in 1988, the FOCAL character set was revised to include more characters, including a number of characters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light-emitting Diode
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared (IR) light. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Early LEDs were often used as indicator lamps, replacing small incandescent bulbs, and in seven-segment displays. Later developments produced LEDs available in visible, ultraviolet (UV) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seven Segment Display
A seven-segment display is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot matrix displays. Seven-segment displays are widely used in digital clocks, electronic meters, basic calculators, and other electronic devices that display numerical information. History Seven-segment representation of figures can be found in patents as early as 1903 (in ), when Carl Kinsley invented a method of telegraphically transmitting letters and numbers and having them printed on tape in a segmented format. In 1908, F. W. Wood invented an 8-segment display, which displayed the number 4 using a diagonal bar (). In 1910, a seven-segment display illuminated by incandescent bulbs was used on a power-plant boiler room signal panel. They were also used to show the dialed telephone number to operators during the transition from manual to automatic telephone dialing. They did not achieve widespread use until the advent of LEDs in the 1970s. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fourteen Segment Display
A fourteen-segment display (FSD) (sometimes referred to as a starburst display or Union Jack display) is a type of display based on 14 segments that can be turned on or off to produce letters and numerals. It is an expansion of the more common seven-segment display, having an additional four diagonal and two vertical segments with the middle horizontal segment broken in half. A seven-segment display suffices for numerals and certain letters, but unambiguously rendering the ISO basic Latin alphabet requires more detail. A slight variation is the sixteen-segment display which allows additional legibility in displaying letters or other symbols. A decimal point or comma may be present as an additional segment, or pair of segments; the comma (used for triple-digit groupings or as a decimal separator in many regions) is commonly formed by combining the decimal point with a closely 'attached' leftwards-descending arc-shaped segment. Electronic alphanumeric displays may use LEDs, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Factorial
In mathematics, the factorial of a non-negative denoted is the product of all positive integers less than or equal The factorial also equals the product of n with the next smaller factorial: \begin n! &= n \times (n-1) \times (n-2) \times (n-3) \times \cdots \times 3 \times 2 \times 1 \\ &= n\times(n-1)!\\ \end For example, 5! = 5\times 4! = 5 \times 4 \times 3 \times 2 \times 1 = 120. The value of 0! is 1, according to the convention for an empty product. Factorials have been discovered in several ancient cultures, notably in Indian mathematics in the canonical works of Jain literature, and by Jewish mystics in the Talmudic book '' Sefer Yetzirah''. The factorial operation is encountered in many areas of mathematics, notably in combinatorics, where its most basic use counts the possible distinct sequences – the permutations – of n distinct objects: there In mathematical analysis, factorials are used in power series for the exponential function an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TI-59
The TI-59 is an early programmable calculator, that was manufactured by Texas Instruments from 1977. It is the successor to the TI SR-52, quadrupling the number of "program steps" of storage, and adding "ROM Program Modules" (an insertable ROM chip, capable of holding 5000 program steps). Just like the SR-52, it has a magnetic card reader for external storage. One quarter of the memory is stored on each side of one card. The TI-58 (May 1977), and later TI-58C (1979), are cut-down versions of the TI-59, lacking the magnetic card reader and having half the memory, but otherwise identical. Although the TI-58C uses a different chip than the TI-58, the technical data remain identical. The "C" in a TI (or Hewlett-Packard) model name indicates that the calculator has a ''constant'' memory (or continuous memory, respectively) allowing retention of programs and data when turned off. These calculators use a parenthesized infix calculation system called "Algebraic Operating System" (AOS) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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