The hand-operated computer was invented in 1878 by Swedish inventor O 'Neill who worked in Russia. This is a gear computer with variable number of teeth.
The main feature of Onnier computer is that the stepped shaft of Leibniz is replaced by a gear with variable number of teeth. Among them, there is no intermediate gear between the word wheel and the base wheel, and the numbers are directly engraved on the gear with variable number of teeth, and the set numbers are displayed in the shell window. It is the predecessor of desktop hand-cranked computer that has been flowing for decades.
19 In the 1980s, all kinds of mechanical computers adopted the method of keyboard setting. Pay attention to the signal bell when dividing the keyboard computer. When there are too many times of subtraction and divisor, it will ring to remind the operation to make up for the subtraction more times. 1905, Germany Jiamen began to use the "proportional lever principle" in computers with keyboard numbers, which made the computer run with low noise and did not need to pay attention to the bell when dividing. This kind of computer has gradually become a widely circulated mechanical computer.
1936 a binary manual mechanical computer produced by Philips company in the Netherlands. Manual mechanical computer has been widely used for a long time because of its simple structure and convenient operation.
Generally, hand-cranked computers can only do four operations: square number, cubic number and square root. If you need to input trigonometric functions and logarithms, you need to look them up. If there are parentheses in the calculation, it will be very troublesome. When using, shake it a few times, shake it a few times, and record it with paper and pen. It was used in the development of China's first atomic bomb.