Exemplary embodiments of the present invention relate to a dimmer for a light emitting device using an alternating (AC) voltage source. The dimmer includes a switch to be switched in response to a switching control signal and to deliver an AC voltage of an AC voltage source to the light emitting device, a current detector to detect an electric current to be provided to the light emitting device and to output a current detection signal, and a controller to output the switching control signal in response to a dimming control signal and the current detection signal.