A mechanical computer is an analogue machine that uses gears, levers and pulleys to represent the process of computation. These devices are not digital computers which use binary numbers to represent data.
The most simple form of mechanical computing device is called a difference engine. It had two sets of gear wheels with teeth cut on both sides of the wheel’s circumference. One set of gear wheels moved back and forth while the other rotated at a constant rate, causing the first set to do work by transferring their rotational energy into linear motion.
This design allowed for multiplication or division calculations by adding or subtracting different amounts from one side until it matched the other side’s value exactly – a method still used in some calculators today!
Examples of Mechanical Computers
Charles Babbage’s “Difference Engine” was a device that could perform addition and subtractions. It was made of sturdy metal and wood, distributed over three major pieces: the ‘mill’, the ‘bed’ and the ‘frame’.
The mill contained two sets of gear wheels which were located face to face. These gear wheels were attached to a drive shaft which was attached to a base of the engine.
The bed contained two more sets of gear wheels, which were rotated by a handle or crank that could be turned by a human operator. The frame had three major components.
The first part held the mill and bed together while the second section housed two small bars on either side of the frame. These bars could be used as adjusting bars to fine tune the gear wheels on both sides of the mill. The third section was a metal bar that ran across the top of the frame and held all three parts together.
The difference engine had limitations, however, which prevented it from being used for more complicated calculations such as polynomials or logarithms. These limitations included the “carry mechanism” (which is now used in modern adding machines) and the limited number of digits it could store (six, due to limited capacity).
The most famous mechanical computer is probably Charles Babbage’s “Analytical Engine”, which was an improved version of his previous difference engine.
The Analytical Engine contained punch cards that could be loaded with sets of instructions for the machine to perform, which were then taken in by an input device called a ‘reader’.
This card reader would grab each card one at a time and take them into the mill section where they would be ‘read’ by a set of brass knobs which turned on a vertical shaft known as the ‘barrel’.
On the other end of this shaft was another set of gear wheels. These worked in much the same way as the previous model, but were able to perform calculations on their input (the value read off the card) and store it in one of several accumulators throughout the machine. The device was capable of performing addition, subtraction, multiplication and division using standard British method (long division).
The Analytical Engine also had limitations that prevented it from being used for polynomial or logarithmical calculations. It was able to store numbers in memory only by writing them into different registers – each location could hold a maximum nine numbers.
This means that if you wanted to write out ten numbers at once you would need ten separate locations. The device was also capable of printing values that were calculated using punched cards, but this was considered a one-off operation and the Analytical Engine was not equipped for printing calculations on paper (although Babbage had suggested such an addition).
The Analytical Engine used many similar components to its predecessor’s design, although the mill section had been improved with a new design. A second input device, called the ‘reader’, allowed for more than one card to be read at once (cards could overlap if necessary) while another mechanism inside the machine allowed for cards which did not match up exactly with their pair in order to accommodate output back into punch cards – it would read each card twice before giving them back.
Mechanical Computers In Modern Society
These simple machines helped in a slow but steady evolution in technology. Since mechanical computers were the predecessor to modern ones, the information that was displayed on the screen would be much more detailed and accurate.
Mechanical computers had a use in business, science, engineering and many other fields. In recent years, there has been a large emphasis put on the use of these simpler computing mechanisms for use in developing countries where it is difficult to obtain access to modern technologies.
The Future Of Mechanical Computing Devices
Modern electronic calculators have all but replaced the use of mechanical computers. Many are finding that these simple computing devices are being used in developing countries to provide basic functions for the workers in the field. With the advent of new technology, it will be interesting to see if these machines will ever be used again.
Electronic calculators and computers are becoming more complex at an incredible rate. Perhaps one day, simple machines like the old adding machine will make a comeback in their simplicity.