Definition

Noun: 1. An electrode placed between the cathode and anode of a vacuum tube to control the flow of electrons through the tube: A control grid is a key component in electronic devices like vacuum tubes (thermionic valves). It is a mesh or spiral of wire positioned between the electron-emitting cathode and the electron-collecting anode. By applying a small voltage to this grid, it can regulate (control) the much larger current of electrons flowing from the cathode to the anode, enabling amplification and switching functions.

Usage Examples

• In early radios and amplifiers, the control grid was essential for signal amplification.
• The technician adjusted the voltage on the control grid to modify the tube's output.
• A vacuum tube typically contains a cathode, an anode, and one or more grids, with the control grid being the primary one for signal input.

Advanced Usage

• Grid Bias: The steady DC voltage applied to the control grid to set its operating point. "The amplifier's distortion was caused by an incorrect grid bias."
• Grid Leak Resistor: A resistor connected to the control grid to provide a path for accumulated charge to leak away.

Variants and Related Words

• Grid (noun): Often used as a shortened, informal form of "control grid" in electronics contexts.
• Screen Grid (noun): A second grid in a vacuum tube (like a tetrode) placed between the control grid and the anode to shield the control grid from the anode's electric field.
• Suppressor Grid (noun): A third grid in a vacuum tube (like a pentode) placed to suppress secondary emission of electrons from the anode.

Synonyms

• Grid Electrode: A more general technical term.
• Control Electrode: A functional description of its role.

Related Phrases

• Grid Voltage: The electrical potential applied to the control grid.
• Grid Current: The small current that flows into or out of the control grid circuit.

Noun

1. an electrode placed between the cathode and anode of a vacuum tube to control the flow of electrons through the tube