This mini LED flashlight is very useful for emergency use. Since it size is small enough to put in your pocket, you can bring it anywhere. This portable LED flashlight is powered by only one AAA battery. To boosting input voltage (1.5V) up to operating voltage of a super high luminosity LEDs -blue, green or white- (3.5V), it uses simple DC to DC converter.
“The circuit is a typical blocking oscillator. High voltage pulse appears at collector of the Q1 (low voltage strobe transistor) is rectified by D1 and charged into C3″, said Elm-Chan, the project designer.