Fluorescent lighting is a popular and efficient lighting system used globally. It is most commonly found in commercial facilities. Fluorescent lamps emit extremely bright glow without getting blistering hot like an ordinary light bulb. They are more efficient as compared to incandescent lamps. Fluorescent lamps and fixtures are certainly more expensive to install than incandescent lighting, but they are significantly cheaper to operate. Besides, the lamps last far longer than incandescent lamps, making the long term cost-of-operation for fluorescent lighting far less than incandescent lighting. Because of their versatility, fluorescent lamps are available in numerous sizes, types, shapes, colors and light intensity. Some are designed to operate in cold locations, while others generate large amounts of light at the expense of service life.
All fluorescent lamps grow dimmer with age, and they may even begin to flicker or flash on and off. These are warning signals, and we should make the necessary repairs as soon as we notice any change in the lamp's normal performance. A dim tube frequently requires replacement, and failure to replace it can strain other parts of the fixture. Also, repeated flickering or flashing will wear out the starter, causing the insulation at the starter to deteriorate.
A Fluorescent lighting system consists of following major components:
- Fluorescent lamp
- Starter system
Based on the particular fluorescent lighting system, the starter may be a replaceable component, a starter may not be required, or the starter function may be integrated into the ballast. The starting function may also depend on the physical design of the fixture.
Basically, a flow of electrical current occurs between two metal conductors placed in a glass tube, a process also known as arcing. That current flow passes through the gases in the tube such as argon and a small amount of mercury in a gaseous phase and excites the atoms of gas. The excited atoms emit photons, some of which are vibrating at a frequency known as ultraviolet light. The ultraviolet light strikes a phosphor coating on the inside of the glass. The phosphor responds to the ultraviolet light by producing a bright visible light. For a fluorescent lamp to start working, the potential of the electricity provided to the electrical conductors called cathodes inside the lamp must be greater than the initial electrical resistance of the gas in the lamp so that the electricity may begin arcing through the gas. There are two ways to overcome this initial electrical resistance:
- Lower the electrical resistance of the gas in the lamp.
- Temporarily raise the electrical potential supplied to the lamp to a level greater than the resistance of the gas, so that arcing may begin.
The Starter or the Ballast creates either or both of these conditions to start the lamp. In actuality, up to half of the wiring in some fluorescent fixtures is used only while starting the lamps. There are three different systems used in starting a traditional fluorescent lamp. They are
- Rapid Start
- Instant Start
- Traditional fluorescent lighting systems are more complex and physically larger than the simple incandescent lamp and socket.
- Initial cost of Fluorescent lighting systems is very high which proves to be a barrier to its wider use.
- Previously, fluorescent lighting likely to only be available in "colder" colors of light than the accepted "warm" color produced by incandescent lighting. The non-warm colors produced by most fluorescent lighting systems found unsuitable for various applications. However, technological improvements have recently produced "warmer" lamp colors and smaller fluorescent lighting systems.