See USB 5V to 1.5V/3V Step Down Converter Circuit using LM317. With this, we can use MP3 players (requires only 1.5V AA battery) with USB(5V).
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.
No light! because of a low voltage battery. How do you increase the voltage up? You can do many ways. And, I recommend a simple step-up converter circuit using TDA2822.
it is the well-regulated power supply. We use it as the simple step down 12v to 9v converter circuit. It can give the output current up to 4A.
This is simple the 12V to 24V step up converter circuit, can convert DCV from 12V to 24V at 1A max. Using TDA2004. Why is amplifier IC? It easy&inexpensive.
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.
Simple Step up DC converter circuit using Transistor 6V to 12V!