A computer is a machine that can be programmed to carry out a set of arithmetic or logical operations automatically. Since a sequence of operations can be readily changed, the computer can solve more than one problem. Conventionally, computers are electronic devices that accept input from an operator and process it according to instructions stored in memory to produce output.
The first computers, as we know them to be, were created in the early 1800s, which we know of. They were called mechanical calculators, and mathematicians and scientists could only use them. Then, in 1876, Charles Babbage designed a machine called the Analytical Engine, which could be programmed to perform any calculation that could be done by hand.
Today, several types of computers are available for other purposes; however, most follow the same basic design initially put forth by Babbage.