Vacuum Tubes

Vacuum tubes are electronic devices that control the flow of electrical current using a sealed glass or metal container with controlled vacuum inside. They typically consist of electrodes such as a cathode and an anode; when heated, the cathode emits electrons, which are directed toward the anode. These tubes amplify electrical signals or switch currents on and off, functioning similarly to modern transistors but using vacuum technology. Widely used in early radios, TV sets, and computers, vacuum tubes were vital for signal amplification and switching before semiconductor devices replaced them due to their smaller size and durability.