As you can see in circuit diagram, this portable solar charger circuit, is based on a LM358N operational amplifier and one transistor. This regulator provide a constant 2. 4 volts DC and can be used for powering small devices that needs to be powered from two AA battery cells. Because the regulator has a low drop down voltage of 0. 3 volt you sho
uld take care about this when you choose solar cells. Maximum load current for this solar charger electronic circuit project is around 125mA typically, enough for small portable devices like radios.