# Cell Phone Charger Circuit

Mobile phones generally charge with 5v regulated DC supply, so basically we are going to build a 5v regulated DC supply from 220 AC. This DC supply can be used to charge mobiles as well as the power source for digital circuits, breadboard circuits, ICs, microcontrollers etc.

You can also build 6V DC, 9V, 12V, 15V etc by using proper transformer, capacitor and voltage regulator. The basic concept remains the same, you just need to arrange a heat sink for higher voltage and current.

This circuit mainly consists a step down Transformer, a Full wave bridge rectifier and a 5V voltage regulator IC (7805). We can divide this circuit into four parts: (1) Step down AC voltage (2) Rectification (3) Filtration (4) Voltage Regulation.

### 1. Step down AC voltage

As we are converting 220V AC into a 5V DC, first we need a step-down transformer to reduce such high voltage. Here we have used 9-0-9 1A step-down transformer, which convert 220V AC to 9V AC. In transformer there are primary and secondary coils which step up or step down the voltage according to the no of turn in the coils.

Selection of proper transformer is very important. Current rating depends upon the Current requirement of Load circuit (circuit which will use the generate DC). The voltage rating should be more than the required voltage. Means if we need 5V DC, transformer should at least have a rating of 7V, because voltage regulator IC 7805 at least need 2V more i.e. 7V to provide a 5V voltage.

### 2. Rectification

Rectification is the process of removing the negative part of the Alternate Current (AC), hence producing the partial DC. This can be achieved by using 4 diodes. Diodes only allow current to flow in one direction. In first half cycle of AC diode D2 & D3 are forward biased and D1 and D4 are reversed biased, and in the second half cycle (negative half) Diode D1 and D4 are forward biased and D2 and D3 are reversed biased. This Combination converts the negative half cycle into positive.

A full wave bridge rectifier component is available in the market, which consist that combination of 4 diode internally. Here we have used this component.

### 3. Filtration

The output after the Rectification is not a proper DC, it is oscillation output and has a very high ripple factor. We don’t need that pulsating output, for this we use Capacitor. Capacitor charge till the waveform goes to its peak and discharge into Load circuit when waveform goes low. So when output is going low, capacitor maintains the proper voltage supply into the Load circuit, hence creating the DC. Now how the value of this filter capacitor should be calculated. Here is the formulae:

C = I * t / V

C= capacitance to be calculated

I= Max output current (let’s say 500mA)

t= 10ms,

We will get wave of 100Hz frequency after converting 50Hz AC into DC, through full wave bridge rectifier. As the negative part of the pulse is converted into positive, one pulse will be counted two. So the Time period will be 1/100= .01 Second= 10ms

V = Peak voltage – voltage given to voltage regulator IC (+2 more than rated means 5+2=7)

9-0-9 is the RMS value of transforms so peak voltage is Vrms * 1.414= 9* 1.414= 12.73v

Now 1.4v will be dropped on 2 diodes (0.7 per diode) as 2 will be forward biased for half wave.

So 12.73 – 1.4 = 11.33v

When capacitor discharges into load circuit, it must provide 7v to 7805 IC to work so finally V is:

V = 11.33 – 7= 4.33v

So now C = I * t / V

C = 500mA * 10ms / 4.33 = .5 * .01 / 4.33 = 1154uF ~ 1000uF

### 4. Voltage Regulation

A voltage regulator IC 7805 is used to provide a regulated 5v DC. Input voltage should be 2volts more than the rated output voltage for proper working of IC, means at least 7v is needed, although it can operate in input voltage range of 7-20V. Voltage regulators have all the circuitry inside it to provide a proper regulated DC. Capacitor of  0.01uF should be connected to the output of the 7805 to eliminate the noise, produced by transient changes in voltage.

Here is the complete circuit diagram for cell phone charger circuit:

You need to be very careful while building this circuit, as AC mains 220V is involved here.

Video:

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• siva

i need a charger circuit

Dec 11, 2015
• Peterwan

Good brother i think the schematic is clearly given on this page(:

Jan 11, 2017
• Diler

What is output of circuit
If lower than 2A how to get it there

Jan 31, 2016
• It will depend upon the Transformer, here 9-0-9 1A Transformer is used.

Feb 08, 2016
• Peter

The 7805 regulator will only supply up to 1A, so the circuit is not suitable for 2A even with a different transformer.

Feb 29, 2016
• Firoza patel

Hi. I'm making a similar circuit and would just like to know the specifications of the full wave bridge rectifier used above.
Thank you

Feb 03, 2016

sir what's value of C2

Feb 04, 2016
• Its mentioned in circuit diagram, its 0.01uF (capacitance code 103)

Feb 08, 2016
• Firoza patel

Hi
I'm making a similar project. I'd just like to know whats the model of the rectifier that you've used.

Feb 08, 2016
• Its 400v 1A Full Wave Bridge Rectifier, can be easily available on any electronics components shop or online stores like ebay.

Feb 08, 2016

How can this circuit be adapted in a locality where voltage fluctuate. What is the efficiency?. From your figure, the voltage measured was 5.11v. How about over voltage, overcurrent protection?ī

Feb 27, 2016
• Peter

I think you have drawn the circuit incorrectly. The way you've drawn it, diodes D1 and D3 short out the transformer output on negative cycles. Your circuit has the junction of D1 and D3 is connected to the transformer centre-tap, although that's not very clear the way you've drawn it.

You need to remove D1 and D3 completely, and the circuit will then work as you meant it to. You do not need and should not use a bridge rectifier with a centre-tapped transformer.

The other way to fix your circuit is not to connect the centre-tap of the transformer to ground, but then you'll have 18v AC across the bridge, which will be about 25v DC, and the regulator will then dissipate a lot of heat.

Also, you should put a 0.1uF or 0.01uF capacitor on the input side of the regulator as well as the output side.

Feb 29, 2016
• manish

How to designe a power supply used for mobiles in which rectifier is used before TRANSFORMER.

Mar 01, 2016
• Leah

Good

Mar 04, 2016
• Jeremy ronquillo

SIr i need help designing a power supply unit that has 5V DC output with 2A. Requirements sais i must use a supercapacitor so that the unit will continue to provide electrical energy for 2 minutes even if the unit is unplugged. I hope i can get a response. Thank youuuu

Mar 17, 2016
• bat-erdenr

I tried this circiut and output is 2.2v i need 5 volt when i missed pls help me iam Mongolia

May 07, 2016
• shinny

Hi Bat-Erdenr,
Could you provide more detail information about your question? Was your experiment result 2.2V? Did you use exactly same components which drawn on this circuit?

May 10, 2016
• Allen

Good day sir! I need to build a 220Vac – 5Vdc, 2A linear power supply. Which of your components do I need to change to accomplish this? Thank you!

May 10, 2016
• Biswanath gorai

I shall try make this charger

May 10, 2016
• Biddut kumar

Thank you for setting

May 11, 2016
• Atchyut Sreekar

I need the output to be 9V and 1.2A. How do I regulate or set the current at the output to 1.2A?
I guess the 78xx series IC's have a maximum current of 1A. Should I use an LM317?
Can I control current at output using additional circuitry?

Jun 01, 2016
• Use 12-0-12 transformer and yes use LM317 for better results.

Jun 11, 2016
• Oba Isaac

Jun 06, 2016
• Vivek

This is a 5V adaptor not charger.

charger circuit is inbuilt in phone which gives 4.2V to battery and does cc+cv+trickle charging.

Jun 16, 2016
• Parag

Sir, i want to make adapter with output 5V , 1A.. please guide me which changes i have to do in above circuit. Thank you.

Jun 20, 2016
• Cvbjjv

How can we increase 1a to 3a

Jun 25, 2016
• Banjo

help in making a 5v 2a adaptor like this

Jul 01, 2016
• @Parag, @Cvbjjv, @Banjo: First you should select the Transformer accordingly, and then you need to select components, that can bear the current according to the Load, so that they wont burn up. Like roughly IC7805 can handle 1A current, depending upon the load.

Jul 09, 2016
• Jasveer Singh

Hello
how to make multiple mobile charger at least 10 mobiles charge at once.

Jul 10, 2016
• Musou

How to make the output becomes 12 V?

Jul 16, 2016
• Jc

Will this circuit still work if i replace the transformer . and make it like in a wireless charger, transmitter coil- receiver coil?

Jul 20, 2016
• Robert Clark

Could you run a phone charger, or any AC/DC adapter, backwards to attach a battery to the output leads and get AC out of the plug?

Bob Clark

Jul 29, 2016
• Melchor

i just have a stu[pid question..can i use the transformer found in the cellphone charger the opposite way?

Aug 01, 2016
• echo

Is it okay to use 5v zener diode and 1k ohm resistor to disipate the ripples?

Aug 11, 2016
• Yes, you can, better use 6v Zener diode.

Aug 13, 2016
• Soumen parui

My cell phone charger out put voltage only .3 volt.It is not desirable.But i can not under stand the problem .Please answer me

Aug 13, 2016
• Chintan

Dear Sir,
I am trying to make mobile charger using wind energy. I also prepared circuit with diode BR10-10, 1000UF/35V CAP., 7805 IC nd 10UF /63V cap. But I am getting only 2mAmp in place of 500mAmp. How can I achieve it? please help me. Nd I also use 500RPM - 12V DC Motor as generator.

Aug 24, 2016

How can I get an output current of 2 amps with 5v/any other voltage ....what are the changes to be made in the circuit toooo....please explain....????

Sep 19, 2016
• Surya

Hey I want the circuit design for making mobile charger........

Oct 24, 2016
• MEHMOOD

hey everybody...i want to design a multiple current ratings charger of values 1A 1.5A 2A....IN A SINGLE BOX...any knowledge about this project ???seriously neede.....

Nov 14, 2016
• Jean Marie

Hello,

i have a generator producing 8V AC 3 phases (3 wires) and i would like to charge my phone at 5V 1A DC
Can i skip the step 1 and directly go to step 2 ?
And how did you calculate the 100 Hz ?

Thank

Dec 01, 2016
• Yes you can skip step first but you also need to consider the current rating your Generator. And AC is of 50Hz so we get 100Hz in DC.

Dec 10, 2016
• Sourav Chakraborty

I need a charger circuit without any tranformar

Dec 07, 2016
• Sourav Chakraborty

How to prepare mobile phone charger without any transformer??

Dec 16, 2016
• Ansar Hussain G...

Sir I want to make charger 5v to 12v Regulated output. what changes are required in this circuit? if we used SCR instead of Diodes what will the result?

Dec 18, 2016
• Sourav Chakraborty

How to prepare mobile phone charger without any transformer??

Dec 18, 2016
• ramoall

I want to prduce modulated phone wave from 1000 to 2500 Hz . and to be able to tune its intesity for biological stuy
many thanks

Dec 19, 2016
• Biju MS

I am trying to make a simple water level indicator using the data taken from internet only. i just wanted to know whether i could replace 9V 1A ac adapter in place of using 9V HW battery for making a simple water level indicator which has resistor 330 ohms and transistor BC 547 in it.

Dec 21, 2016
• Sravankumarneela

As in transformer o/p power =i/p power then how the electronic devices are working at our homes because of this high i/p power of a transformer.

Dec 21, 2016
• mohamed Azeem

how to 5v ?

Dec 22, 2016
• Mary Jane

Good Day Sir,,

what transformer should i use in reducing AC 85 - 270 v.

Jan 03, 2017
• tonny Anthony

How do i use a transformer with 11v output

Jan 05, 2017