These devices are necessary for the operation of certain light sources. They primarily refer to current-limiting control gear (chokes) and starters, i.e. ignitors, required to operate discharge lamps but also to transformers required to operate low-voltage halogen lamps. Inductive control gear devices are available either in conventional (CCG) or low-loss versions (LCG). They sometimes require an additional ignitor or starter. Electronic control gear (ECG) work without any additional ignitor and prevent annoying transformer hum or stroboscopic effects.