This document presents a portable emergency mobile charger circuit. The circuit allows users to charge their mobile phones when a power source is not available. It consists of two parts: a battery charger and a mobile phone charger. The battery charger converts 220V AC to 12V DC and charges a 12V lead-acid battery. The mobile phone charger then takes the 12V from the battery, regulates it to 3.7V, and outputs it through a USB port to charge phones. The circuit allows phones to be charged on the go using the stored battery power.

1. Emergency Mobile Charger
Project Report
Created By :
Armughan Bhutta
Group Members :
Muhammad Akmal Noor
Tahir Raza Jilani

2. Abstract :
In this report we are going to introduce you with
unique type of cell phone charger which is
Portable/Emergency Mobile Charger.
Purpose :
Cell phones have become a necessity for many
people throughout the world. The ability to keep in
touch with family, business associates, and access
to email are only a few of the reasons for the
increasing importance of cell phones. Today's
technically advanced cell phones are capable of not
only receiving and placing phone calls, but storing
data,even can be used for taking pictures .
These has only power source is rechargeable
batteries. Today’s smart phone can withstood
maximum one day of charging.
When we are on long route or out of station we
couldn’t find any proper way for charging cell
phone we need power backup to operate our
devices. So that need lead us to make such a
circuit that store charge and at the time of need
we can utilizes that for charging our devices.

3. Components :
 Transformer:
We used a center-taped stepdown
transformer for getting 12 volts from 220 AC.
 Diode :
Two types of diodes are used in this
circuit for rectifying the voltage and are listed
bellow :
1.1N4007
2. Zener 11v 0.5W
 Regulator :
Two types of Voltage Regulators are
also used which are listed bellow:
1. LM317T
2.LM7805
 BJT :
A BD139 is used to measure the charged
voltage of the Battery.
 Resistors :
There are many different values
resistors are there in the circuit to manage and
control the flow of current.

4.  Battery :
12volts Ni Battery is used to store the
charge for providing uninterruptable supply.
 Power Cable :
Power cable is used to connect circuit
to AC Voltage source.
 USB Port :
From USB Port we take output
 Data Cable :
It is used to attach the Cell Phone to
charge it.

5. Circuit Diagram:
Part 1(Battery Charger):
Part 2(Mobile charger):

6.  Working :
Circuit is basically consists of two parts 1 is Battery
charger and other is mobile charger.
First of all the circuit is connected to AC Voltage
source through power cable and then the 220 volts
AC stepdown to 12v and then this AC is passed
through diodes to convert it to DC .
After passing through the diodes we get pulsating DC
Then there is a capacitor ahead to smoothen the
pulsating DC after capacitor the voltage is not
complete smoothen then we pass this to LM317T
regulator which completely smoothen the 12volts DC
ahead of this there is a battery to store the charge .
Now the current inters the 2nd
part of circuit which
take 12v from battery and convert it to 3.7v and we
get output from an A-TYPE USB-Port then through
data cable we can charge our device.
This converging takes place as, first the voltage from
battery passes through a capacitor and then it passes
through a regulator which take 12v input and gave
us 4v output ahead of this there is again a capacitor
which smoothen they any fluctuation present in the
output wave form.
The output is connected with USB-Port then this is
connected to device which have to be charged.