1970s to mid-1980s

The first Pocket calculators

By 1970 a calculator was made using a few chips with low power consumption, this allowed portable models to be powered from rechargeable batteries. The first portable calculators started in 1970 in Japan. The models first introduced were; the Sanyo ICC-0081 "Mini Calculator"; the Canon Pocketronic and the Sharp QT-8B "micro Compet".

The Canon Pocketronic was an expansion of the "Cal-Tech" project which had been initiated at Texas Instruments in 1965. The Pocketronic had no traditional display as the numerical output was on thermal paper tape. Texas instruments was granted master patents on portable calculators due to it's project.

In 1971 the Sharp EL-8, also marketed as the Facit 1111 which was much nearer to a pocket calculator as it weighed about one pound. It had a vacuum fluorescent display, and was powered by rechargeable NiCad batteries. Initially the unit sold for $395.

In 1971 the MK6010 by Mostek, (the first "calculator on a chip"), was developed by Texas Instruments later in the year. These early hand-held calculators were extremely expensive yet, these advances in electronics, together with further developments in display technology (such as the vacuum fluorescent display, LED, and LCD), lead to the cheap pocket variety being the first calculator available to all, within just a few years.

In 1971 the first calculator (of the electronic variey), that was realistically pocket-sized was the Busicom LE-120A "HANDY". This was the first calculator to use an LED display. It also was the first hand-held calculator to use a single integrated circuit.

In 1971 the first American-made pocket-sized calculator was also introduced. The Bowmar 901B (often referred to as The Bowmar Brain ), came out in the fall of 1971. It had four functions, and an eight-digit red LED display, it retailed for $240, but the four-function Sinclair Executive became the first slimline pocket calculator which retailed for around $150 (GB £79). However by the end of the decade, similar calculators were priced less than $10 (GB £5).

In 1973 the first Soviet-made pocket-sized calculator was introduced; the "Elektronika B3-04" was developed, and it retailed at the start of 1974.

In 1973 one of the first calculators that was low-cost was launched; the Sinclair Cambridge. It retailed for £29.95, or about £5 less in kit form. The Sinclair calculators were successful as they were cheaper than others of the time albeit, their design was flawed, and their accuracy in some functions was questionable.

In 1973 , the SR-10 was introduced by Texas Instruments (TI), it was an algebraic entry pocket calculator retailing for only $150. It was then followed in 1974 by the SR-50, which added log and trig functions in order to compete with the HP-35.

In 1974 the first calculator that was programmable and pocket sized was the released, the HP-65. The HP-65 had a capacity of 100 instructions, it could also retrieve and store programs with a built-in magnetic card reader.

In 1975 the HP-25C introduced continuous memory , so programs and data were stored in CMOS memory even during power-off.

In 1977 the first Soviet programmable calculator, the Elektronika B3-21 was developed and sold by the beginning of 1978 . The successor of B3-21, the Elektronika B3-34 was not backward compatible with B3-21, even if it kept the RPN. So the B3-34 needed a new command set, which then was used in all of the programmable soviet calculators later on

The slide rule became obsolete by the end of the 1970s.

Technical improvements

The 1970s saw rapid improvement in the hand-held electronic calculator. The red LED and the blue/green vacuum-fluorescent displays consumed a lot of power so calculators either had a short battery life, or were so large to accomodate higher capacity batteries. In the early 1970s Liquid crystal displays (LCDs) had not been around long, so there was much concern about their operating lifetime. Busicom introduced the Busicom LE-120A "HANDY" calculator. It was the the first pocket-sized calculator with an LED display. However, there were problems with the display, so the calculator never went on sale. The first calculators with LCDs to be retailed were manufactured by Rockwell International, and they sold from 1972 . The LCDs were in an early form, so the numbers appeared as silver against a dark background.

In 1972 Sharp Inc launched a more successful series of calculators using the reflective LCD display, with the Sharp EL-805 . This slim pocket calculator and another few similar models, used Sharp's "COS" (Crystal on Substrate) technology. This used a glass-like circuit board which was also an integral part of the LCD.

In the mid-1970s the first calculators were retailed, with LCDs with dark numerals against a grey background (these are still used today), the early developments however, often had a yellow filter over them to cut out damaging UV rays. The main advantage of an LCD is it is passive, and reflects light thus requiring much less power than actually generating light. This development saw first credit-card-sized calculators, for example the Casio Mini Card LC-78 of 1978 , which could run for months of normal use on just 2 of button cells.

Improvements were also made in the electronics inside the calculators. All of the logic functions of a calculator had been included into the first "Calculator on a chip" integrated circuits in 1971 , however this was leading edge technology of the time and yields were low, and costs were very high. Many calculators used two or more integrated circuits (ICs), especially the scientific and programmable ones even into the late 1970s.

The power consumption of the integrated circuits was reduced as well. The introduction of CMOS technology appeared in the Sharp "EL-801" in 1972 . The transistors in the logic cells of CMOS ICs just used any significant power when they changed state. The LED and VFD displays required additional driver transistors or ICs, whereas the LCD displays were driven directly by the calculators IC alone.

In 1978 calculators such as the Royal Solar 1 , Sharp EL-8026 , and Teal Photonwere released, manufacturers had realized the low power consumption could make use of solar cells as a power source

Mid-1980s to present

In 1985 the first graphing calculator, the Casio fx7000G was released.

In 1987 the first calculator capable of symbolic computation was introduced, in the HP-28. It was able to solve quadratic equations symbolically.

At the turn of the 21 st Century, the differences in a graphing calculator and a handheld computer was no longer clear, as some advanced calculators such as the HP-49G, theTI-89 and the Voyage 200 and could differentiate and integrate functions, solve differential equations, run word processing and PIM software, and also connect by wire or IR to other calculators/computers.

In 1981 the HP 12c financial calculator was introduced produced, and is still being made with very few minor alterations. The HP 12c features the reverse Polish notation mode of data entry and by 2003, several new models were released. These included a improved version of the HP 12c, the "HP 12c platinum edition." This added more memory, saw an increase in built-in functions, and the an addition with algebraic mode of data entry.