control grid

electronics

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 24, 2026

Quick Summary

In electronics, a control grid is an electrode within an electron tube, typically positioned between the cathode and the anode (plate). Its primary function is to modulate or control the flow of electrons through the tube.123

This control is achieved by applying a small voltage to the grid, which can significantly alter the electron stream reaching the anode. This capability makes the control grid a crucial component for amplification and oscillation in devices like triodes, tetrodes, and thyratrons. While newer technologies have largely replaced vacuum tubes, the principles of the control grid remain fundamental in understanding early electronic circuits.345

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

5 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

triode
…of its amplification function, the control grid is generally the most important and critical electrode in a vacuum tube. A small variable voltage applied to the grid can greatly modulate the flow of electrons reaching the plate. The control grid is normally a wire mesh that intercepts little or no…
Read More
…of its amplification function, the control grid is generally the most important and critical electrode in a vacuum tube. A small variable voltage applied to the grid can greatly modulate the flow of electrons reaching the plate. The control grid is normally a wire mesh that intercepts little or no…
Read More

grid
…fixed potential—is placed between a control grid and an anode to reduce the electrostatic influence of the anode on the control grid. A suppressor grid is interposed between two positive electrodes—usually the screen grid and the anode—to reduce the flow of secondary electrons from one to the other.
Read More
…fixed potential—is placed between a control grid and an anode to reduce the electrostatic influence of the anode on the control grid. A suppressor grid is interposed between two positive electrodes—usually the screen grid and the anode—to reduce the flow of secondary electrons from one to the other.
Read More