Many times it happens that we forget to carry power bank with us and our mobile also run out of battery, In this instructable, i have build a simple yet useful circuit by which you can charge your cellphone from general purpose 9V battery or a 12V battery.
The circuit uses only few components and is very cheap and portable.
Step 1: Components Required
Following components are required to build this circuit
1) 7805 IC
2) 9V battery
3) Small Heatsink
5) Female USB connector
Step 2: Schematics
In the schematic shown, 7805 IC is acting as a heart of the system.
7805 IC is a very cheap 5V linear regulator.
Being a linear regulator, you can't expect high efficiency from 7805, but yes it can save your life sometime.
Step 3: Connections and Setup
I mounted the 7805 IC on a small heatsink and then i secured 9V battery connector on the top of the heatsink using glue gun.
I also secured the female USB socket on the heatsink using hot glue gun.
Step 4: Testing the Circuit
By this time, the setup was almost complete and was ready to be tested.
I connected the circuit to the 9V battery and then used a USB cable to connect the circuit to the cellphone, the cellphone started charging as can be seen in the image.
Finally the project was successfully completed.