Patent ID: 7239041

Claim:
A light emitting device adapted to be applied with one of an AC input power signal and a DC input power signal, said light emitting device comprising: an input node set adapted for receiving said one of the AC and DC input power signals and including first and second nodes; a light emitting unit including at least one light emitting element connected across said first and second nodes; an impedance matching element having a first end connected electrically to said first node, and a second end; a switch unit connected between said second end of said impedance matching element and said second node; and a control unit connected in parallel to said light emitting unit and connected to said switch unit, said control unit being operable so as to control said switch unit to operate in one of an ON-state, where said switch unit makes connection between said impedance matching element and said second node when said first node is applied with the AC input power signal, and an OFF-state, where said switch unit interrupts connection between said impedance matching element and said second node when said first node is applied with the DC input power signal for a predetermined period.