Simple Power Bank
I am using LM7805 voltage regulator to control the voltage required voltage for charge a smart phone is 5 Volt DC supply That why I use LM7805 voltage regulator because it is a five volt voltage regulator
Connect Input and Output Wire
Solder according the circuit diagram first pin of LM7805 is input postive and the third pin of LM7805 is output postive and the second pin that is center pin is negative pin which is common for both input and output
Checking the Voltage Level
Before using it in smart phone check the output voltage by using multimeter output must be 5 volt
Output
connect the output of LM7805 voltage regulator to USB jack based on the pin configuration
Final Output
take a suitable box for a battery and better look
Testing
Video LINK youtube link