Types of Calculators

Several types of calculating machines 9’re available in the market. Let us discuss about some of them.

1. Key-driven Calculator: It has a full-bank keyboard. When keys are pressed, the numbers are shown on the dial. Multiplications are made by repeated additions and similarly, divisions are made by repeated subtractions. For instance, to multiply 3 by 3 is pressed three times.
2. Rotary Calculator: This machine may be operated manually ‘or electrically. It requires the number to be entered on the keyboard by pressing the key and I operating the lever to record the number on the dial. The results are obtained by turning the respective crank-handle clockwise for addition or multiplication, and anti-clockwise for subtraction or division.
3. Electronic Calculator: It is a miniature desk-size computer-operated electronically with the aid of valves or transistors. It operates at a very fast speed and does not make any noise. An electronic calculator can be operated by electricity or battery and it may be a full-bank or ten-key type. It displays the figures of the calculations on a small screen which is activated by a cathode-ray tube simi4ar to that used in a TV set.
4. Printing Calculator: It looks like an adding/listing machine and may have a full bank keyboard or ten-key board. It is very easy to operate. The keys are pressed to register the figures for calculation. Then the symbol key (for multiplication, addition, etc.) is pressed and the answer is obtained by a pressing device which stores the desired figures until required, and then it can be added or subtracted. Transfers can also be made to the memory register and vice versa.