Patent ID: 8866392

Claim:
A two-level LED security light, comprising: a light emitting unit; a loading and power control unit; a light sensing control unit; a motion sensing unit; and a power supply unit; wherein the light emitting unit comprises at least one LED; wherein the loading and power control unit comprises a microcontroller electrically coupled with a transistor, wherein the transistor is electrically connected in series with the power supply unit and the light emitting unit, wherein the microcontroller with program codes outputs a pulse width modulation (PWM) signal to a gate electrode of the transistor to control the conduction period T on and the cut-off period T off of the transistor for delivering different average electric currents from the power supply unit to drive the light emitting unit for generating different illuminations, wherein the microcontroller controls the transistor respectively to have a short T on and a long T on of the conduction period such that the light-emitting unit respectively generates a low level and a high level illumination according to the received signal outputted from the light sensing control unit and the motion sensing unit.