There are basically two types of Fluorescent lamps used for general lighting currently available on the market today, conventional Fluorescent and Cold Cathode Fluorescent.

Linear and Compact Fluorescent (CFL) Lamps

Fluorescent Lamps have been around for many years now. In 1859 experiments showed that certain substances gave off light when they were placed in an evacuated glass tube and an electrical current passed through it. Later thin coatings of luminescent materials were placed on the surfaces of these tubes. Fluorescence occurred, but the tubes were very inefficient and had a short operating life.

The Modern fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor coating on the inside of the glass to fluoresce, producing visible light.

Unlike incandescent lamps, fluorescent lamps always require a ballast to regulate the flow of power through the lamp. However, a fluorescent lamp converts electrical power into useful light more efficiently than an incandescent lamp. Lower energy cost typically offsets the higher initial cost of the lamp. While larger fluorescent lamps have been mostly used in large commercial or institutional buildings, the compact fluorescent lamp is now being used as an energy-saving alternative to incandescent lamps in homes. Compared with incandescent lamps, fluorescent lamps use less power for the same amount of light, generally last longer, and initially more expensive than a comparable incandescent lamp. However the savings made over time will pay for the lamps very quickly indeed. 

Linear Fluorescent Lamps

Compact Fluorescent Lamps

Cold Cathode Fluorescent Lamps (CCFL)

Most fluorescent lamps use electrodes which operate at a high enough temperature for the chosen material (normally a special coating) to liberate electrons across to the gas-fill by heat.

However, there are also tubes which operate in cold mode, whereby electrons are liberated only by the level of potential difference provided. This doesn't mean the electrodes are cold (and indeed, they can be very hot), but it does means they are operating at a lower tempurature. This means they can have much longer lives than is commonly available with conventional fluorescent tubes, and this makes them desirable for maintenance-free long-life applications. The other advantage to this product is that it can be dimmed in most cases unlike conventional Fluorescent lamps. The easiest way to tell the difference between the CFL and a CCFL is the diamiter of the glass used as the light source, as seen below.

Cold Cathode Fluorescent Lamp

Controlled Plasma

Controlled Plasma down lighting combines a high efficiency light source with patented controller technology to provide the first of a new breed of compact, long life, cost and energy efficient lighting.

The Controlled Plasma light source provides higher efficiency than previous incandescent, fluorescent and compact fluorescent technologies and offers longer life in a compact form. Harsh lighting and shadows are avoided with the uniform and controlled illumination patterns possible with Controlled Plasma.

Controlled Plasma: CP1 Fitting and Globe