ملفات خانقة فعالة

لاحظ أن هذا النوع من الملفات لا علاقة له بالماء (حيث يسمي الصابورة في حالة الماء) ولكن باللمبات

Ballast (electrical)
An electrical ballast is a device intended to control the amount of current flowing in an electric circuit.
Ballasts vary greatly in complexity. They can be as simple as a series resistor as commonly used with small neon lamps. For higher-power installations, too much energy would be wasted in a resistive ballast, so alternatives are used that depend upon the reactance of inductors, capacitors, or both. Finally, ballasts can be as complex as the computerized, remote-controlled electronic ballasts used with fluorescent lamps.