Friends may meet the disadvantages of the electrical equipment that uses battery be battery like to finished the climax always. This equipment no help to give battery be finished have power upward again. But wait for warn when battery low be hurried change or charger to first be finished. This circuit designs to come to apply to volt since 3-15V the dot will to begin to show can fine with VR1. When voltage decrease down more location dot keeps LED bright immediately. The electronics part a little also just transistor BC547 and other. It usual Current about 3mA but enough LED bright will valuable about 15mA.
