Several electronics companies and inventors may claim a first when it comes to the development of the electronic calculator. Japanese company Sharp is said to have created the first desktop calculator, the CS-10A, in 1964. This model resembled a cash register and cost about as much as mid-sized car [sources: Lewis, Sharp]. In 1967, Texas Instruments developed what is known as the first portable, handheld calculator -- a device that could perform addition, subtraction, multiplication and division -- in a project that the company nicknamed "Cal Tech" [sources: Courier Mail, Texas Instruments].

Using "Cal Tech" technology, Canon developed the first handheld calculator for commercial use, which debuted in 1970 with a price tag of $400 [source: Texas Instruments]. The next few years became something of a race between manufacturers to make calculators smaller, more accessible and less expensive. In 1972, British inventor Sir Clive Sinclair introduced the Sinclair Executive, which is considered by many to be the world's first affordable pocket calculator [sources: The Press, Western Daily Press]. Its thickness was that of a pack of cigarettes.

These continued advancements in calculator technology were largely made possible by the development of the single-chip **microprocessor** in the late 1960s. Before this time, engineers built the computing "brains" of calculators (and computers) with multiple chips or other components. Basically, a single-chip microprocessor allows an entire central processing unit (CPU) to exist on one silicon microchip. (To learn more about this technology, check out How Microprocessors Work.)

Intel Corp. created the first commercially available single-chip microprocessor -- the Intel 4004 -- in 1971 [sources: Behar, Intel]. It was capable of performing basic arithmetic, 4 **bits** of information at time. However, Intel's co-founder, Gordon Moore, predicted that the capacity of a single chip would double about every two years. This theory is known as "Moore's Law," and so far it still holds true. Not only did calculators become smaller over the years, they became capable of increasingly advanced applications [source: Intel].

Today, in addition to modern versions of the basic pocket calculator, complex scientific and graphing calculators are available and used by both students and professionals such as engineers. Many use well-known computer languages and are programmable according to the user's needs. In fact, when Texas Instruments introduced its TI-92 model in 1995, they called it "a calculator with the power of a computer lab" [source: Texas Instruments]. Many scientific and graphing calculators may be capable of some of these functions:

- Switching from the usual base-ten to other number systems (hexadecimal counting, is a base-16 system)
- Using scientific notation to calculate very large numbers
- Using logarithms and trigonometric functions directly
- Working with constants like pi and e at a much higher degree of accuracy
- Using complex numbers, fractions and formulas
- Solving equations
- Analyzing statistics
- Using larger displays to work out formulas and graph equations

Read on to the next section to find out more about solar cells, circuit boards, and some of the other parts that make up a calculator.