Small appliances have microcomputer that requires 5V power supply. Why it can use only 1.5V battery? The 1.5V to 5V boost converter circuit inside them.
This circuit offers a variety of Buck DC to DC converters. Because as circuit increase voltage as the usb 5v to 12v dc-dc step-up converter. This circuit is called Boost converter circuit.
This high power led flashlight circuit look like torch by 1.5V battery only so it can be used, small so Easy to carry in various places,also very bright [...]
This is 5V to 12V boost converter circuit or higher using transistor circuit,When if you want a negative voltage from a positive power supply.