PORTABLE ELECTRIC LAMP PROVIDED WITH A DEVICE FOR AUTOMATICALLY ADJUSTING THE ILLUMINATION

The lamp (10) has a light source (114) comprising sources for generating a light beam. A power unit (110) controls brightness of the beam in response to control information or a control signal. A control unit generates the control information or the control signal, and comprises a photo sensor (122) and a regulating circuit controlling a switch-off phase of wide and narrow beams during a period invisible to a holder of the lamp. The switch off phase is combined with a measure of diversity made by the photo sensor on reflective ambient environment.