Gasudladningsrør

Gasudladningsrør, or gas-discharge tubes, are a class of electrical devices that conduct electrical current in a gas. This conduction occurs when a high enough voltage is applied across the gas, causing it to ionize and become a plasma. The tube itself is typically a sealed glass or quartz vessel containing a specific gas or mixture of gases at a low pressure. Electrodes are placed at either end of the tube to facilitate the flow of electricity.

When a sufficient voltage, known as the breakdown voltage, is applied, the free electrons within the gas are accelerated. These electrons collide with neutral gas atoms, knocking off more electrons in a process called ionization. This creates a chain reaction, leading to a significant increase in conductivity and the emission of light. The color of the emitted light depends on the type of gas used. For example, neon gas produces a characteristic red-orange glow, while argon can produce a blue or violet light.

Gas-discharge tubes have found various applications throughout history and in modern technology. They were historically used in lighting, such as neon signs and fluorescent lamps, where the emitted light is used for illumination. They also function as voltage regulators, surge protectors, and in specialized scientific instruments. The principle of gas discharge is fundamental to many plasma-based technologies.