The present invention generally provides a power control unit adapted to provide adjustable levels of a controlled output power signal, such as but not limited to a pulse width modulated signal or a serial binary signal. One embodiment of a power control unit according to the present invention comprises a housing holding internal electronic components. This housing further comprises input and output wiring extending out of the housing and internally connected to the electronic components. The electronic components further comprise circuitry capable of providing at least 2 levels of the controlled output power signal. The present invention also includes lighting systems incorporating a power control unit according to the invention.