Abstract: A lighting apparatus includes a light source, a main controller, a AC-DC converter, a dimmer signal extractor, a dimmer interface circuit and an isolating transformer. The AC-DC converter converts an external AC power to a driving current of a DC power for supplying power to the light source according to a control signal received by the main controller. The dimmer signal extractor generates the control signal supplied to the main controller according to a transformed signal. The dimmer interface circuit is connected to a dimmer. The dimmer is disposed on a wall to be operated by a user to generate a dimmer voltage. The dimmer voltage is converted to a dimmer signal. The isolating transformer has a secondary terminal connecting to the dimmer interface circuit and a first terminal connecting to the dimmer signal extractor.