This universal battery charger electronic project is designed using the LM317 voltage regulator and some other electronic components .
As you can see in this schematic circuit this battery charger has extreme few components , but is doing a very good job . When power is applied to the circuit the SCR1 is off, so there is no bias-current path to ground.
This USB car charger adapter project is a DC DC power converter that safely converts the 12V car battery voltage into stable 5V. This USB car charger circuit can be used to supply power from a car cigar lighter socket to a portable device that require a 5 volts . This circuit makes it possible to power/recharge any USB power-operated device, using in-dash board cigar lighter socket of your car.