Energy-conserving devices of illumination systems

Disclosed is an energy-conserving device for an illumination system. The energy-conserving device is connected between a power supply of and a lighting assembly of the illumination system. The energy-conserving assembly provides a first switch, a ballast, and a compensating capacitor. The ballast is connected between the power supply and the lighting assembly, and connected between the first terminal and the second terminal of the first switch. The compensating capacitor is connected between the power supply and a third terminal of the switch. The energy-conserving device may further include a resistor and a second switch which are connected in parallel with the ballast. The energy-conserving device can be coupled to a conventional illumination system and is of energy-conserving, a low cost and a long lifetime.