Neon signs are a type of gas-discharge lamp. They create light by ionizing an inert gas, such as neon or argon. The mercury vapor that is struck by the high voltage at the electrodes makes it glow like a fluorescent lamp. The answer is yes, neon signs can be dimmed, but there are some things to consider when doing so: -Most commonly used neons with HID ballasts may not be dimmable. -It is always worth a try. The sign may have been wired incorrectly, or the ballast may not be properly programmed. -Transformer-based neon signs (two-wire) are more likely to be dimmable than those with isolated power (three-wire). -Most transformers do not function correctly if operating on less than 120 VAC. -AC-powered neon signs require a special bulb and set of components that are dimmable.