A flashlight or portable light source has a battery power source, a light source, a circuit powered by the battery power source which causes the light source to emit light in an on state, a switch which causes the circuit to alternate between the on state and an off state in which the light source does not emit light when the switch is actuated by a user, a controller for causing light emitted from the light source to emit at two or more modes other than the off state, and an automatic dimmer residing within the flashlight which causes light emitted from the light source to dime without any activation of the switch after a first preselected amount of time.