gas-filled converter

A gas-filled converter is a device that utilizes the presence of a gas to alter the conductivity between electrodes, differing from a vacuum tube. These devices are commonly used for rectification and switching applications, such as controlling inductive energy-storage circuits or performing modulations. Examples include thyratrons and ignitrons.1

In a gas-filled converter, a low-voltage discharge is initiated, ionizing the gas. Electrons from this ionization then bombard the cathode, generating secondary electrons that sustain the discharge. Some of these electrons are accelerated, causing further ionization and forming a plasma. When this plasma connects the electrodes, a conduction path is established, allowing current to flow. This current can be interrupted by a control grid.1

Thermionic power converters, which convert heat directly into electricity, can also be gas-filled. In these devices, the space between electrodes is filled with a vapor or gas at low pressure. This allows for the creation of a plasma that neutralizes the space charge, facilitating electron flow from a hot emitter to a cooler collector.2