What is discharge tube?

A discharge tube is a sealed glass tube filled with a gas at low pressure, used to study electrical discharges and the behavior of gases under electric fields. When a high voltage is applied across the electrodes within the tube, it ionizes the gas, allowing current to flow and producing visible light, often in vibrant colors depending on the gas used. Discharge tubes are fundamental in demonstrating principles of atomic and molecular physics, as well as in applications like neon signs and gas lasers.