The history of computing devices began with basic tools like fingers for counting and the abacus. During the 17th and 18th centuries, inventors created early mechanical calculating devices. The first real calculating machine was invented in 1820 using gear wheels. Charles Babbage then designed the Analogue Engine in 1830, an early mechanical general-purpose computer, but it was never completed. The first digital computers were developed in the 1940s and used vacuum tubes, followed by transistors in the 1950s which led to smaller, faster computers. Integrated circuits were introduced in the 1960s and have since gotten smaller through microminiaturization, leading to increasingly faster computers with each new generation.