Car mobile phone charger circuit diagram

Remove the shell of an abandoned but still usable mobile phone charger, remove the original 220V voltage through the capacitor step-down and diode rectifier, and connect the 12V car plug of the cigarette lighter in the car with the 12V input terminal in the picture. Connect, and then measure whether the voltage at the output terminal corresponds to the charging voltage of the mobile phone, 4.2~5V. If it is normal, just fix the charger in a place out of the way. Pay attention to isolation around the installation part to prevent short circuit.

If the output voltage is slightly lower than the user's mobile phone charging voltage, the optocoupler current limiting potentiometer RP needs to be adjusted appropriately so that a suitable charging voltage can be obtained.