What are the components of a calculator?« Back to Questions List

A completely human operated tiny machine that can do amazing calculations within seconds is a calculator. Though it needs a good knowledge of electronics to understand how a calculator works, it is easy to learn about the components of a calculator.


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A calculator has a processing unit to perform the mathematical functions and an input/output device to interact with the user. There is a keyboard which acts an input device that takes in the input from the user. There are about 40 tiny keys with a rubber membrane underneath and a touch-sensitive circuit below that. The narrow display screen on which we see the display (of input as well as the output) is a LCD (liquid crystal display) screen. Calculators need a long life battery or they may also use a solar cell which uses power of the sunlight. The brain of the calculator is a microchip which performs the hard mathematical operations within seconds using the concept of binary operation.




Let us see what happens when we try to add two numbers (say 20 + 40). When you press a number, the button makes an electrical contact with the keyboard sensors found below the keyboard. The keyboard circuit detects the number and processor will keep on displaying the numbers entered as long as the mathematical operation keys (like +, -, *, / etc) are pressed. Once you press a function key, the processor stores the number entered before (20), in a small memory called register. When we enter the next number (40), the number gets displayed till the ‘equal to’ (=) symbol is pressed. When it is pressed, the second number gets stored in another small register and finally contents of both the registers are added and displayed.


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