How Do Neon Signs Work?
The Science Behind the Glow
Neon signs have been lighting up businesses and streets for over 100 years—but what exactly makes them glow?
At their core, neon signs are made of glass tubes filled with gas, bent into shapes and letters. When high voltage electricity is sent through the gas, it glows. That’s the short answer. Here’s a deeper look at how it all works.
What’s Inside a Neon Sign?
Each neon sign contains a few key components:
- Glass Tubes: Hand-bent into custom shapes or letters
- Electrodes: Sealed at each end of the tube to carry current
- Inert Gas: Usually neon (red/orange) or argon with mercury (blue/white)
- Transformer: Converts normal voltage to 3,000–15,000 volts to power the sign
The tubes are sealed so the gas stays inside. When energized, the gas emits visible light.
Why Does Neon Glow?
It comes down to excited gas particles. When the high-voltage current hits the gas inside the tube, it excites the gas atoms, making them jump to a higher energy level. As they settle back down, they release energy in the form of light.
- Neon gas glows red-orange.
- Argon with mercury glows blue.
- Different colors are created by using phosphor coatings inside the glass or mixing gases.
What Makes the Glass Tubes?
Neon tubing is shaped using heat and skill. A technician (also known as a glass bender) uses a flame to soften the glass and shape it into curves, corners, and letterforms. It’s a specialized craft, and each tube is made by hand.
After shaping, the tube is cleaned, connected to a vacuum pump, and filled with the correct gas. Electrodes are attached, the tube is sealed, and then tested with a transformer.
How Are Neon Signs Powered?
Neon signs run on high voltage, low current electricity. That’s why they use special transformers to step up the voltage. This power pushes current through the gas inside the tube, causing it to emit light.
Most signs plug into standard wall outlets, but the transformer inside boosts the power enough to light the gas consistently and safely.
Are Neon Signs Dangerous?
When properly installed and maintained, neon signs are safe. However, they do operate at high voltage, so if wiring is damaged or a transformer fails, there is a risk of shock.
Signs should be serviced by qualified technicians. If you see flickering, hear buzzing, or notice part of the sign isn’t lit, it’s time for a check-up.
Can Neon Signs Be Repaired?
Absolutely. Broken tubes, bad electrodes, and faulty transformers can all be repaired or replaced. At NYC Neon Repair, we handle repairs, LED conversions, vintage restorations, and new installs across NYC and surrounding areas.
If your sign isn’t lighting up properly, send us a photo and location—we’ll provide a quote with no surprises.
Summary: How Neon Signs Work
Neon signs light up when electricity passes through gas-filled glass tubes, causing the gas to glow. With the right gas, transformer, and craftsmanship, these signs create that classic vibrant glow that’s instantly recognizable.
They’re a mix of science, skill, and art—and we’re proud to keep them glowing.
