Compact Fluorescent Lamps

The compact fluorescent lamp is a type of bulb which is commonly known for its efficiency for using less power than other commonly used bulbs, whilst still emitting the same amount of lighting. 

CFLs have been designed in order to replace the incandescent lamp and can fit into most existing lighting fixtures that may have previously been used for incandescent bulbs.

When you compare the two (CLS and Incandescent) the incentive to use CLS shows due to the lower power usage for the amount of light emitted and its longer life span. Although the CLS bulbs are usually more expensive, in the long run they are also more cost affective too.

As usual for fluorescent lamps, CFLs contain mercury, which complicates the process of disposal. For more information please see:

Disposal & Recycling of low energy bulbs

Components

They have two main components, a gas filled tube and a magnetic or electronic ballast. Electronic ballasts have a small circuit board which have rectifiers, a filter capacitor and in most cases two switching transistors which are connected as a high frequency. 

The high frequency from this is applied to the lamp tube, which will be around 40kHz or even higher.

The problem with CFL bulbs, when compared to other bulbs, is that they take slightly longer to heat up after being switched on, showing a delay in the progression of lighting. While incandescent bulbs reach there full brightness a fraction of a second after being turned on, some CFL bulbs can take up to a minute.