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Calculator, a device that immediately performs mathemathial calculations on numbers that are entered into the device by an operator. Today's calculators are electronic digital systems that work very much like computers. The differences between calculators and computers will be discussed later. Many people ask what is pay scale calculator. General Characteristics Calculators range in size from desktop models through hand-held units to miniature systems the size of a credit card. All have a keyboard of pushbuttons for entering numbers, commands, and perhaps letters. All except some desktop models have a display showing numbers or alphanumeric characters (letters, numbers, and symbols). Some hand-held calculators, and most desktop types, have built-in printers that record information on paper tape. Many people ask what is pay scale calculator. Many calculators can only perform addition, subtraction, multiplication, division, and perhaps square roots. These are called simple or four-function calculators. Some four-function calculators can store a number other than the one being worked on and displayed. 
Advanced calculators have keys for more functions than the basic four and square root. In "scientific" calculators, this includes functions such as sine, cosine, logarithms, and so forth. "Business" calculators have keys for automatically performing several complex sequences of steps for calculations commonly used in business. An example would be figuring payments on a loan. Many people ask what is pay scale calculator. 
Advanced calculators also allow storage and retrieval of several or many numbers. This involves keyboard commands such as "Store in Register A" and "Recall from Register A." Some calculators let the operator enter a sequence of calculation steps as an algebra equation, using parentheses to separate expressions. The most advanced calculators are "programmable" devices. Sequences of commands keyed in by the operator can be stored for future use with different sets of input numbers. These sequences, called programs, resemble computer programs. In some cases, the programs can include "branch" and "loop" statements as in a computer program. However, machines with branch and loop capabilities are usually called computers instead of calculators. Many people ask what is pay scale calculator. Differences Between Calculators and Computers Programmable calculators operate so much like computers that there is no definite rule for distinguishing such calculators from very small, self-contained computers. Probably the most widely accepted distinction is this: programmable calculators have separate memory systems, discussed later, for data (numbers being worked on) and programs. This concept, called "Harvard architecture," is suitable for the style in which commands and numbers are entered in a calculator but not for computer languages. Computers, by contrast, store both data and programs in the same memory system. This is called "Von Neumann architecture." Computer programming languages (such as BASIC) require this design concept. Many people ask what is pay scale calculator. Principles of Programmed Digital Systems Like other digital systems, calculators use integrated circuits (IC's). An IC contains a chip of silicon, no bigger than a fingernail, in which thousands of circuit elements such as transistors are fabricated. The type of IC typically used is called MOS (metal-oxide-semiconductor). In all but the most advanced calculators, the circuitry is contained entirely on a single MOS IC. A typical calculator may consist only of a case, a keyboard, an IC, a display unit, and either a battery or a solar-power panel. In a digital system information is carried from point to point by switching conductors (wires or the equivalent) back and forth between two voltage states. In this way a conductor carries one "bit" of information, which is defined as either 0 (zero) or 1 (one). Where a bit must be stored within the circuitry, there is a transistor circuit that remains in one state until forced to change by certain input signals. Alphanumeric characters (numbers and symbols) and commands or instructions are carried and stored as groups of bits called words, bytes, or nibbles. In a computer, numerical data are handled in binary (base 2) code. For example, the number 13 would be 1101, meaning one 8, one 4, no 2, and one 1. In contrast, a typical calculator uses the binary-coded decimal (BCD) form. Numbers remain in decimal (base 10) form, but each digit is coded as a separate 4-bit binary number. For example, the number 13 would be 0001 0011. The 0001 stands for the 1 in the tens place, and the 0011 stands for the 3 in the ones place. |
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