Electronic ballasts for fluorescent lamps 
These ballasts consist generally of a rectifier and a high frequency inverter. They operate the fluorescent lamp at high frequency, typically around 30kHz.
Electronic ballasts represent the state-of-the-art in ballast technology. They offer significant advantages compared to electromagnetic ballasts:
- Electronic ballasts have relatively low losses similar to the best magnetic ballasts. In addition, fluorescent lamps have a higher efficacy when associated with an electronic ballast producing around 20% more light than when operated at the same power at 50Hz.
- They impose softer starting conditions on the lamps. This leads to longer lamp life, and hence reduced maintenance costs; in addition, multi-switching operation will have less effect on life as occurs, for example, if presence detectors are used in the installation.
- One electronic ballast can operate up to four lamps together while their magnetic counterparts can operate one to two lamps.
- Electronic ballasts are lighter, particularly for larger lamp sizes.
- They offer more accurate control of lamp power and current.
- Fluorescent lamps on electromagnetic ballasts flicker 100 times a second whereas on electronic ballasts they turn on and off more than 40.000 times a second, invisible even sublimely. There is evidence that the incidence of headaches and eyestrain is less under high frequency fluorescent lighting than under conventional mains frequency fluorescent lighting.
- At present electronic ballasts are more expensive than wire-wound (magnetic) ballasts. However, prices are getting cheaper.
Electronic ballasts can be used almost everywhere. Some electronic ballasts provide warm starting for the lamp and are particularly suitable where frequent switching occurs. Other cold start the lamp and are more suitable for lamps with long running hours and few switching actions.
With suitable controls further energy savings can be achieved by dimming in response to available daylight whitin the building, and allowing the occupants to set the levels to suit their particular needs. Dimmable electronic ballasts, also called “class A1 ballast” in the manufacturers' classification, can be:
- Full range dimming ballasts which can continuously adjust the light output of the lamp down to 20%, 10% and even 1.5% depending on the type of ballast and lamp.
- Step dimming ballasts which offer a number of different light level outputs (but no continuous dimming).
The non-dimmable electronic ballasts are contained in two classes A3 and A2 in the manufacturers' classification.
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