Because of their power requirements, the earliest pocket calculator displays - LED, vacuum fluorescent, Panaplex, and so on - greatly limited the size to which calculators could be shrunk and placed considerable limits on battery life. The key to miniaturization lay in the development of low-drain liquid crystal displays. Sharp Electronics (formerly Hayakawa Electric), always at the forefront of calculator design, realized this early on, devoting substantial resources to LCD research and development. Between 1973, when they introduced the world's first LCD pocket calculator, and the early 1980s, Sharp produced a remarkable series of pocket calculators using LCDs. For the most part, these calculators were not cheap throwaway units; to the contrary, they were stylish and inventive. They introduced numerous innovations that are now commonplace.
Sharp used three different types of LCD: initially, the COS-LCD (defined variously in Sharp ads as Crystal on Substrate, Calculate on Substrate, and Calculator on Substrate), which showed numbers on a silver background and required shading from bright light, then the yellow-screen FEM (Field Effect Mode) type, and the gray-screen FEM type, which is the type in use today. Theories abound as to why so many early LCD calculators used the yellow-screen display, the most common one being that it served as protection from "damaging" UV light until the technology was perfected to prevent that. However, I have dual-display calculators (for calculations and time) that have both a gray and a yellow display; furthermore, some manufacturers, including Sharp, manufactured gray-screen models along with or even preceding yellow-screen ones.
This article attempts to make sense of the numerous models Sharp produced during this period by grouping them according to characteristics in common. Following the model number in parentheses is my estimate of the year of introduction. The dates are derived from the 1st digit of the serial number (which in Sharp's case always seems to equate to the year of manufacture), Sharp sales brochures, and other printed sources.
First models: EL-805, 805M, 805S, and 808 (all late 1973), EL-807 (1974). These classics have Sharp's unique silver-colored COS-LCD display and a pop-up hood to better render the display in bright light. The 805 series were advertised as operating for 100 hours on a single AA battery, a real breakthrough for the time. The 805 units are therefore quite compact, while the 808 is a larger coat-pocket size model. They were popular units, extensively advertised and receiving favorable reviews in consumer magazines, but surprisingly did not take the calculator world by storm, and are relatively difficult to find today. I know of two clones of the 805: the first Russian pocket calculator (Elektronika B3-04), and the Privileg Mini Computer, which was sold in Germany. The 805 "S" version featured a brighter display, a locking on/off switch, and a CE key. The 807 is a particularly rare model. It requires 2 AA batteries and has a stylish black and silver faceplate.
All-metal COS: EL-8010 (1975), 8015 (1976), 8110 (1975). These units continued to use the COS-LCD with pop-up hood concept; indeed, the 8010 is probably the most commonly found model of this type. Clad in a slim all-metal case and contained in a wallet-type folding carrying case, these surely rank as among the more intriguing calculators of the era. The 8110 is the memory version of the 8010, and also has more of a gold tone to the metal. The 8015 says "Electronic Calculator" on the front of the unit, but otherwise apears identical to the 8010.
Folding: EL-8009 (1975), 8009S (1975), 8019 (1976), 8039 (1978), 8039G (1978). One might say that these were the first clamshell calculators, as they folded in two into a very compact package. The display half was connected to the keypad half via thin bendable metal strips, another technological breakthrough for Sharp. The 8009 and 8009S versions (the "S" model has separate "Clear" and "Clear Entry" keys) use the COS type display, the 8019 has the yellow-screen display, and the 8039/8039G versions ("G" model is gold-toned), the gray display. The 8039/8039G also use a membrane keypad, which will be discussed in a later section.
First FEM: EL-8020 (1976), 8021 (1976), 8025 (1977), 8120 (1976). Sharp's first calculator using the yellow-screen FEM-type display was the EL-8020 and its memory counterpart, EL-8120. These models first appeared in early 1976, but had been preceded by Casio's Pocket LC, which was released in late 1975. They were quite elegant, made of two-tone brushed aluminum with a gold-tone finish, and only 7 mm thick.
Membrane keypad: EL-8036 (1977), 8130 (1977). Another Sharp breakthrough was the development of the membrane, or flat, keypad, which allowed the calculator to shrink even further to only 5 mm in thickness (the 8130 was called the "super thinman"). Since the keys lack any tactile response when pushed, these units had a special key which activated a beep that sounded upon each key press. This "sensor touch" key, used in many later Sharp calculators, had a musical note symbol on the key.
Credit card: EL-8140 (1978), 8141 (1979), 8145 (1978). Actually, only the 8145 is oriented horizontally like a credit card, but all three are clearly of the same family, sharing a common size, membrane keypad, and similar graphic design. These units are a remarkable 3.5 mm thick, and actually smaller than a credit card in the other dimensions. At this point, the calculators are becoming so minuscule that they are almost impractical to use.
Storage computer: EL-8150 (1978), 8152 (1979), 8155 (1978). These models all have a "storage computer" facility prominently marked on the front of the unit (as do some of the "credit card" models mentioned above). This feature is similar to the standard memory feature, except it uses a "compute" key to accomplish memory multiplication on the number entered via the "store" key (useful for performing a series of conversions, for instance) and retains the stored contents even when the calculator is shut off. The 8150 and its gold-toned counterpart, 8155, are only 4 mm thick. All are sleek and elegant in appearance, with the 8150 and 8155 having slightly recessed keys.
Special mention must be made of the EL-8152. This "storage computer" unit is an astonishing 1.6 mm thick (that's 1/16"!), thin enough to earn a place in the Philadelphia Museum of Art's Post-War Japanese Design exhibit of several years ago (the only pocket calculator in the exhibit). Sharp has referred to this unit as the world's thinnest calculator of its time; it is no doubt a tour de force of miniaturization. Whether it was the first unit of this size is subject to debate: Casio produced the LC-79, a calculator of approximately 2 mm thickness (1.9 mm was stated in Casio advertising), as early as 1977, according to Casio's records.
Sharp in 1985 upstaged the 8152 with a model only half as thick (0.8 mm!), the EL-900. I have never seen one, but believe it is of the credit card style, which became popular in the mid-'80s. Casio's SL-800, of similar thickness, appeared in 1983.
Scientific: EL-5804 (1976), 5805 (1977), 5806 (1977), 5808 (1978). These models all featured transcendental functions, such as logarithms, exponents, and trigonometric functions. Sharp's first LCD scientific model, the 5804, is an unusual unit, in that it has a horizontal, slim (7 mm) ruler style and features a black faceplate. The 5805 and 5806 have a much more conventional appearance, similar to the 5000 series fluorescent display models of that period. The 5808 features a membrane keypad with circular key boundaries, certainly one of the more unusual scientific calculators ever made.
Programmable: EL-5100, 5101, 5102 (all 1979). The 5100 series calculators have proven to be very popular among collectors, and it is easy to see why. They were precursors to the pocket computer that Sharp developed in 1980 and sold as the Radio Shack PC-1 or Sharp PC-1200. They also had some interesting features such as a scrolling display and alphanumeric capability. The 5100 could hold 80 program steps and had a 24-character display, while the 5101 could handle 48 program steps and had a 16-character display. The 5102 is a financial model, making it one of the very early programmable financial calculators. These all have the yellow display.
Time functions: EL-8138E (1978), 8143E (1978), 8144E (1979). These units were quite thin (6.5 mm for the first two, less than 5 mm for the 8144E) and had a multitude of time functions, including a clock, alarm, stopwatch, and some calendar functions. The 8144E is a particularly nice unit, well designed and somewhat scarce, and with a membrane keypad.
Executive look: CT-500 (1977), CT-510E (1978), CT-600 (1978), CT-610 (1978). Seemingly designed with the executive in mind, the CT series calculators featured world-time and calculator functions in elegant packages. The 610 even featured a built-in radio. The 600 models were larger units designed to be placed on a desk; the 500 series were gold-toned folding models for the pocket. Both the 510 and 610 had membrane keypads.
Talking calculators: EL-620 (1981), 640 (1982). In these, as keys are pressed, a voice indicates what has been pushed and then relates the result. The 640 was sold for quite a while, at least up until 1991.
Pocket printer: EL-1195 (1981). A small "thinman" printing model with a gray display, this model measures only 5" x 3" by 0.5", not quite as small as Olivetti's Logos 9, but the smallest unit of its kind that Sharp produced.
Other interesting models
EL-8008 (1975): Definitely a one-of-a-kind calculator in Sharp's lineup, this all-plastic early COS-LCD unit has a lever on one side of the display hood to facilitate lifting and quirky '70s styling. It resembles some of the plastic fluorescent display models that Sharp was producing in the mid-70s, notably the EL-8005. One of the rarest of all the models listed in this article.
EL-8026 (1976): Sharp's (and quite possibly the world's) first solar-powered pocket calculator, this model resembles the EL-8020 in styling, and has a thickness of only 1/2". It was nicknamed the "Sunman" by Sharp, in contrast to some of their other calculators, which were given the "Thinman" name. The most interesting feature of this calculator is the placing of the large solar panel on the back of the unit! Yellow display. Very difficult to find.
EL-8029 (1977): A ruler-style unit with pocket clip that bears some similarity to the TI Data Clip and Canon Ruler-8 of the same year, but with the added ability to fold in two. Opened, it is only 6.5 mm thick.
EL-8048, 8148 (about 1979): Combination abacus/calculator. Yes, you read correctly - one side has an abacus, and next to it is an electronic calculator. A characteristic of Japanese design, especially during this period, is the tendency to combine several products into one package (calculators have been combined with radios, lighters, tape recorders, pens, musical keyboards, and so on). This is one example that has a wonderful symmetry to it, combining the most ancient of calculating devices with the most modern. I am not absolutely certain as to the model numbers, so please contact me if I'm wrong about that.
EL-8153, 8159 (both 1979): Similar in appearance to the storage computer models, but without that feature. About 5 mm thick.
EL-8156 (1979): A metric conversion unit in light brown plastic. In the early to mid-70s, many manufacturers introduced metric conversion models in response to the movement in the U.S. to switch to the metric measurement system. By the late 70s, however, interest had subsided and these calculators no doubt sold poorly. As a result, this model is somewhat rare.
EL-8160 (1979): One of the first calculators to use a dot-matrix display, alphabetic characters, and a rolling display - all in a rather colorful pocket unit with a yellow display and recessed keys. Another rare one, and another unit I've seen pictured in a Japanese design book.
EL-8061S (about 1979): Called the Hang-a-Round. This one is a very tiny metal unit, similar to the Casio Micro-Mini, with a gold metal lanyard attached to it so the calculator can be hung around ones neck.
EL-208 (1979): Although the LCD allowed the use of much smaller batteries, a 9-volt is required to power this one. It has a severely angled look to it, with the back being much higher than the front to accommodate the battery (similar to the Commodore Minuteman 6). I have both a yellow-screen and a gray-screen version. The back of this model is a unique brick red color.
Other models from 1976 to 1980
Sharp produced many other LCD calculators during this prolific period, but in my opinion they weren't as interesting as the many models discussed earlier. For the sake of completeness, however, here is a list of some that show up now and then:
1976: EL-8024 (yellow screen, nice
Collecting Sharp LCD calculators
Despite their more recent vintage, as a whole these calculators are more difficult to find than Sharp's LED or fluorescent display models. Indeed, many of them are quite scarce. The more common models tend to be the less interesting ones on the last list in the article. Among the more desirable models, the easiest to find are the EL-8010, 8110, 208, and 1195. Less common but still available from time to time are the EL-8029, 8130, 8145, 5100, and maybe the CT-600 and EL-5804, 5805, and 5806. An 805 shows up occasionally, as does a folding model. The rest I would characterize as scarce or rare (i.e., I've seen anywhere from zero to perhaps two examples in the few years I've been intensively searching for them). Among the important units, the rarest appear to be the EL-807, EL-8008, EL-8026 "Sunman", 8036, 8140, 8144E, 8152, 8155, 8160, and 5808.
When found, they often show signs of use and age. Common problems are scratching and scuffing of the metal surfaces, missing screws that hold the backs on, battery corrosion, and darkening of the edges of the yellow displays. However, these calculators are of recent enough vintage so that occasionally new-in-the-box examples turn up.
Interest in them is currently very low and for most of the public these are throwaway items, so bargain prices are the rule rather than the exception. Collector prices run about $15 for just the calculator and case, up to $25 or so for a new-in-box example. The 805 models, 5100 series, and the abacus/calculator can fetch $50-$100 or even more in certain circumstances. I have no data on the rarest models, but surmise that some of them have potential value of $50 or more.
Copyright @2001 Larry Gilbert