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The core component described is a vacuum tube switch, comprising a cathode and an anode sealed within an evacuated tube. When the switch is "open," the contacts are physically insulated from each other, preventing current flow. To close the switch electronically, the cathode is heated, causing it to emit electrons—a process known as thermionic emission.
By applying a positive potential to the anode, a current path is established. Electrons emitted from the heated cathode are attracted to the positively charged anode, creating a flow of charge that effectively closes the switch and allows current to pass through, powering devices such as motors.
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