Conventional ballasts (CB/KVG)
Conventional ballasts are choking coils consisting of a number of turns of copper wire around an iron core. For the operation of a fluorescent lamp an external ignition device known as a starter is also required. To compensate reactive power (power factor Lambda < 0.5), a capacitor is used. Characteristics: high construction.

Starter serve as ignition support: When power is applied, a glow discharge takes place which heats a bimetal contact. A second or so later, the contacts close and provide current to the fluorescent filaments. Since the glow is extinguished, there is no longer any heating of the bimetal and the contacts open. The inductive kick generated at the instant of opening triggers the main discharge in the fluorescent tube.

EVG High-frequency electronic ballast (EB)

Resistance cables reduce the voltage down to the service voltage of the lamp. The necessary ignition voltage is reached by using an integrated starter. As the cable itself is the conductor and offers a certain resistance measured in OHM/m the cable must not be shortened in any way. Lamps operating with resistance cable are not allowed in the EU. However, some countries tolerate the sale and operation, since there is no danger, if used properly. Recognizeable due to the blue conductor. Here a thin resistance wire is wrapped around artificial silk, in order to reach a charge of 200 Ohm/m (for a 8 Watt fluorescent tube)

GVG /RB Rectifier ballast
(Special type of electronic ballast used mostly in handlamps)

Most hand lamps are operated by rectifier ballasts. Here the energy comes in by a conventional cable. The current is transformed inside electronic parts on the plate of the ballast. These electronic parts balance the current supply and can avoid tension peaks. The current drop-out underneath the service voltage caused by sinusoidal fluctuation effects the tube to be turned on and off 100-120 times/s depending on the power-supply system. Thus the tube flickers in denpendence on the frequency of the local power-supply system which means that the so-called stroboscopic effect can arise. Rectifier ballasts can be applicated with resistance wire which is placed inside the lamp in order to balance fluctuations and tension peaks within the power-supply system in a better way. Rectifier ballasts are destroyed, if the fluorescent tube is breaking or has reached the end of its lifetime. If the lamp is not moved during permanent service the so-called rectifier effect can arise. This means that the fluorescent tube becomes darker in one of its half.

Technical hints

EEI - Classification

In order to be able to compare the power absorption of ballasts and lamp circuits a proposal to set the standard for the measurement of the total output of ballasts and lamp circuits was published by CENELEC (Comité Européen de Mormalisation Electrotechnique=European Commitee for Electrotechnical Standardization). The Federation of National Manufacturers Association for Luminaires and Electrotechnical Components for Luminaires in the European Union (CELMA) has introduced a classification for ballasts and lamp circuits. According to this, the total output of ballasts and lamp circuits is devided into 7 classes per lamp type (see table). The classes A1, A2 and A3 are determined to electronic ballasts (EB) (A1 dimmable)

-classes B1 and B2 are determined to low-loss ballasts (LLB and -classes C and D to conventional electromagnetic ballasts (CB conventional ballast). It is planned to prohibit the application of class C (exclusion from 21st May 2005) and D(exclusion from 21st November 2002) in the first step. For classes B1 and B2 there will be a little longer transition period, so that soon only luminaires with electronic ballasts are allowed to be sold.