A dimmable light emitting diode (LED) lamp is provided. The dimmable LED lamp includes an alternating current (AC) input unit and at least one AC detection unit connected to the AC input unit. The dimmable LED lamp also includes at least one LED driving and power supply unit and at least one LED light source assembly, where the LED driving and power supply unit is connected to the LED light source assembly. Further, the dimmable LED lamp includes at least one controller with a pulse width modulation (PWM) output, wherein the AC detection unit is connected to the controller, and the controller is connected to the LED driving and power supply unit.