LM317 12 volt battery charger electronic circuit design

This 12 volt battery charger is based on LM317 three terminal regulator manufactured by National Semiconductors which is one of the most used three terminal regulators from the market and can be can be used to design a very simple 12 volt battery charger electronic project using few external electronic parts. Because of the high efficiency provided by the LM317 and number of low parts required this integrated regulator can be used in many power supply circuit projects .

RS sets output impedance of the car battery charger Zout-Rs=(1+R2/R1) .
Use of RS allows low charging rates with fully charged battery. The 1000 μF is recommended to filter out input transients .