A pentode is a type of vacuum tube or thermionic valve that contains five active elements: a cathode, an anode, and three grids, which are used to amplify electronic signals. It improves upon the design of the triode by adding a screen grid and a suppressor grid, which enhance performance by reducing capacitance and preventing secondary emission effects.

Pentode

pentode

Vacuum tubes are electronic devices that control electric current flow in a high vacuum between electrodes to amplify, switch, or modify a signal. They played a crucial role in the development of early electronics, including radios, televisions, and computers, before being largely replaced by semiconductor devices like transistors.

vacuum tube

thermionic valve

active elements

A cathode is the electrode through which electric current flows out of a polarized electrical device. In electrochemical cells, it is the site of reduction reactions, attracting cations or positive charges from the electrolyte.

cathode

The anode is the electrode where oxidation occurs in an electrochemical cell, and it is crucial for the flow of electrons in the circuit. In galvanic cells, it is the negative terminal, while in electrolytic cells, it is the positive terminal, demonstrating its role in different types of electrochemical reactions.

anode

three grids

amplify electronic signals

A triode is a type of vacuum tube with three elements: a cathode, an anode, and a control grid, used to amplify electrical signals. It played a crucial role in the development of early electronics, including radio, television, and early computers, before being largely replaced by transistors.

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