Tyhjiöputkikeräinten

Tyhjiöputkikeräinten, also known as vacuum tubes or electron tubes, are devices that control electric current flow in a vacuum between electrodes. They were the primary active components in electronic equipment from the early 20th century until the mid-20th century, when they were largely replaced by semiconductor devices.

A typical vacuum tube consists of a sealed envelope containing a filament and one or more electrodes. The filament, heated by an electric current, emits electrons. These electrons are attracted to the anode, a positively charged electrode, and flow through the tube to complete an electric circuit. The tube's behavior can be controlled by the voltage applied to the grid, a third electrode that can attract or repel the electrons.

Vacuum tubes were used in a wide range of applications, including radio transmitters and receivers, television broadcasting and reception, and early computers. They were known for their ability to amplify signals and their high power output, but they were also large, fragile, and had a limited lifespan.

The development of vacuum tubes was a significant milestone in the history of electronics. They enabled the creation of complex electronic systems and laid the groundwork for the development of modern electronics. However, their eventual replacement by smaller, more reliable, and more efficient semiconductor devices marked a turning point in the field.