Free Sample
The Complete Handbook of Fluorescent Tubes
For professionals, businesses, and serious hobbyists who install, maintain, specify, or resell fluorescent lighting systems
by Alumigogo Books
Chapter 1: Understanding Fluorescent Tubes
Fluorescent tubes light roughly 80 percent of commercial office space in North America. They illuminate warehouses, factories, schools, hospitals, parking garages, and retail stores. Yet most people who work with them—electricians installing them, facility managers maintaining them, business owners paying the electricity bills—operate largely on instinct and habit. They change tubes when they burn out, replace ballasts when fixtures stop working, and decide whether to retrofit to LED based on conflicting advice from salespeople and online forums.
This chapter explains how fluorescent tubes actually work, why that matters, and why they remain so prevalent despite competition from newer technologies.
What a Fluorescent Tube Is
A fluorescent tube is a sealed glass cylinder filled with a low-pressure mixture of inert gas (usually argon) and a small amount of mercury vapor. The tube's interior surface is coated with phosphor powder—a material that emits visible light when struck by ultraviolet radiation. The tube has electrodes at each end. When current flows through the gas, it ionizes the gas atoms, causing them to collide with mercury atoms. These collisions produce ultraviolet light. That UV light hits the phosphor coating, which converts it into visible light.
The tube cannot start or operate on standard household electrical current. It requires a ballast—an electrical device that limits current flow through the tube and provides the initial voltage surge needed to ionize the gas. The ballast sits outside the tube, typically inside the light fixture housing or mounted separately nearby.
A complete fluorescent