Cell Phone Charger Circuit


ByJayant 91

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.

full wave rectifier

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.

Full Wave Bridge Rectifier


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.

Voltage Regulator 7805 Pins



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

Cell Phone Charger Circuit Diagram

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


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  • siva's picture
    Dec 11, 2015

    i need a charger circuit

  • Peterwan's picture
    Jan 11, 2017

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

  • Muashra Nabi 's picture
    Muashra Nabi
    Mar 26, 2018

    Sir i don not know how to connect transformer to the circuit.

  • Diler's picture
    Jan 31, 2016

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

  • Maddy's picture
    Feb 08, 2016

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

  • Peter's picture
    Feb 29, 2016

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

  • Firoza patel's picture
    Firoza patel
    Feb 03, 2016

    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

  • Muhammad afzal's picture
    Muhammad afzal
    Feb 04, 2016

    sir what's value of C2

  • Maddy's picture
    Feb 08, 2016

    Its mentioned in circuit diagram, its 0.01uF (capacitance code 103)

  • Firoza patel's picture
    Firoza patel
    Feb 08, 2016

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

  • Maddy's picture
    Feb 08, 2016

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

  • Ade Bab's picture
    Ade Bab
    Feb 27, 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

  • Peter's picture
    Feb 29, 2016

    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.

  • Annie_M's picture
    Feb 07, 2018

    With the transformer shown as connected in the schematic (ie 9-0-9 - centre tap), you do not need & should not use a bridge rectifier, the common earth on the -ve side of the rectifier and the centre tap will sohort circuit one of the windings. If you use a single winding transformer, use a bridge rectifier; if you are using a cenrre tap transformer, use 2 individual rectifer diodes thus: the centre tap of the transformer is used as the -ve supply to the circuit & the two other winding ends go through the diodes which are commoned to gether at their + ends. This commoned connection is the +ve supply to the circuit.

  • manish 's picture
    Mar 01, 2016

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

  • Jeremy ronquillo's picture
    Jeremy ronquillo
    Mar 17, 2016

    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

  • bat-erdenr's picture
    May 07, 2016

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

  • shinny's picture
    May 10, 2016

    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?

  • Allen's picture
    May 10, 2016

    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!

  • Biswanath gorai's picture
    Biswanath gorai
    May 10, 2016

    I shall try make this charger

  • Biddut kumar 's picture
    Biddut kumar
    May 11, 2016

    Thank you for setting

  • Atchyut Sreekar's picture
    Atchyut Sreekar
    Jun 01, 2016

    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?

  • Maddy's picture
    Jun 11, 2016

    Use 12-0-12 transformer and yes use LM317 for better results.

  • Oba Isaac's picture
    Oba Isaac
    Jun 06, 2016

    What about inverter

  • Vivek's picture
    Jun 16, 2016

    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.

  • Parag's picture
    Jun 20, 2016

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

  • Cvbjjv's picture
    Jun 25, 2016

    How can we increase 1a to 3a

  • Banjo's picture
    Jul 01, 2016

    help in making a 5v 2a adaptor like this

  • Abhishek's picture
    Jul 09, 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.

  • Jasveer Singh's picture
    Jasveer Singh
    Jul 10, 2016

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

  • Musou's picture
    Jul 16, 2016

    How to make the output becomes 12 V?

  • Jc's picture
    Jul 20, 2016

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

  • Robert Clark's picture
    Robert Clark
    Jul 29, 2016

    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

  • Melchor's picture
    Aug 01, 2016

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

  • echo's picture
    Aug 11, 2016

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

  • Soumen parui's picture
    Soumen parui
    Aug 13, 2016

    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

  • Chintan's picture
    Aug 24, 2016

    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.

  • Jagadeesh's picture
    Sep 19, 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....????

  • Surya's picture
    Oct 24, 2016

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

  • MEHMOOD 's picture
    Nov 14, 2016

    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.....

  • Jean Marie 's picture
    Jean Marie
    Dec 01, 2016


    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 ?


  • Maddy's picture
    Dec 10, 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.

  • Sourav Chakraborty's picture
    Sourav Chakraborty
    Dec 07, 2016

    I need a charger circuit without any tranformar

  • Sourav Chakraborty's picture
    Sourav Chakraborty
    Dec 16, 2016

    How to prepare mobile phone charger without any transformer??

  • Ansar Hussain Gilgiti's picture
    Ansar Hussain G...
    Dec 18, 2016

    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?

  • Sourav Chakraborty's picture
    Sourav Chakraborty
    Dec 18, 2016

    How to prepare mobile phone charger without any transformer??

  • ramoall's picture
    Dec 19, 2016

    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

  • Biju MS's picture
    Biju MS
    Dec 21, 2016

    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.

  • Sravankumarneela 's picture
    Dec 21, 2016

    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.

  • mohamed Azeem's picture
    mohamed Azeem
    Dec 22, 2016

    how to 5v ?

  • Mary Jane's picture
    Mary Jane
    Jan 03, 2017

    Good Day Sir,,

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

  • tonny Anthony's picture
    tonny Anthony
    Jan 05, 2017

    How do i use a transformer with 11v output

  • Maddy's picture
    Jan 28, 2017

    You can use 11v transformer with this circuit, current rating should be less than 1A, what is the current rating of your transformer?

  • Anik's picture
    Feb 10, 2017

    Please tell me why my mobile charger is showing charging but battery is not charging what could be the problem in any mobile?

  • Pushpak's picture
    Mar 03, 2017

    Hello sir i need sm help please
    i hv transformer now its giving me dc output is near 13v but i wanted to charge my my 2.4v Ni-mh battery so i used 8v mosfet or i think its called as voltage regulator LM7808 and created a circuit but did not work my battery isn't charging...(i checked it using multimeter it gives 7.98v) but its not working at all i dont kno why i need sm solution or is thr any way to increase output voltage of mobile charger like my android charger gives 5v output so if i can increase it to 7-9 v ? please help me out

  • Pushpak's picture
    Mar 04, 2017

    i want to make charger thats gives at digit dc voltage between 7-10 v dc so i can charge my2.v battery using it
    it wud be a big help of some1 show me how to increase voltage of normal mobile charger
    thank you

  • Pushpak's picture
    Mar 05, 2017

    wow kind of a voltage regulator...thank you maddy but can u suggest me sm quick and lil cheap method...

    and can use smtng else instd of LM317

  • Chiranjeeb's picture
    Mar 04, 2017

    i have done it but the percentage of battery coming down, what could do to up the percentage

  • Andrew's picture
    Mar 05, 2017

    which capacitor can i use when designing a mobile charger AC12 input?

  • bahaa's picture
    Mar 27, 2017

    What should we have to do if we need output current of 2A

  • Firdous Khosa's picture
    Firdous Khosa
    Apr 15, 2017

    Input is 100-220v~ 50-60Hz 1.5A
    Output 19V=4.74A

  • Faizal's picture
    Apr 21, 2017

    good day sir..

    may i know, what is the function for C1 capacitor?
    thank you.. sorry for my bad english..

  • sushahs's picture
    May 14, 2017

    sir i want to make a fast charger which out put has 5 volt and 3 amp, do you have any diagram ?????????
    i have already 3500 map lipobattrie

  • Andrew Sims's picture
    Andrew Sims
    May 31, 2017

    Thank you Sir, I have copied the end of the circuit, after the bridge rectifier, because I don't need it as I am using a DC Motor. The Motor is rated 12V so the Voltage Regulator with the same Capacitors should do the job nicely, providing a 5V output to a mobile phone or power bank. Would I put a 100ohm resistor in my final circuit?

  • Shahzaib Asif's picture
    Shahzaib Asif
    Jun 10, 2017

    How many ampere it gives at output ?

  • Talha Tanveer's picture
    Talha Tanveer
    Jun 19, 2017

    why you didn't used a resistor in smoothing?

  • Usama Ejaz's picture
    Usama Ejaz
    Jul 05, 2017

    Sir you just made my concepts better,

  • James's picture
    Jul 07, 2017

    All chargers av seen contains resistors in them , why is that ?

  • ajay's picture
    Aug 19, 2017

    What happen if I connect a 7V DC motor directly to a 220V AC supply by a charger and datacable
    Is it work or get any short circuit???

  • Aswinth Raj's picture
    Aswinth Raj
    Aug 20, 2017

    Assuming your chargers output to be 5V 2A. Yes you can do it. It will not create a short circuit. 

    But, it is not an effective way of doing it. Because the 7V motor will be powered by 5V which will force it to consume more current and eventually damage it.

    So this will be a temporary solution only.

  • vishu's picture
    Aug 23, 2017

    i need block daigram and circuit daigram power supply. one input and meny outputs.but output current will be different

  • Rajiv rajput's picture
    Rajiv rajput
    Aug 28, 2017

    LED in mobile charger is not glowing and mobile also is not charging..so, i want to take a risk of removing LED and joining both ends..will it work..what is the significance of LED apart from glowing indication..?

  • Aswinth Raj's picture
    Aswinth Raj
    Sep 01, 2017

    LED is given for indication purpose. Removing it might not help.

    Which LED are you talking about? There is no LED in the circuit diagram

  • Bhavesh Chudasama 's picture
    Bhavesh Chudasama
    Oct 05, 2017

    1 Hors 80 % Mobaile Chargin & All Compny Mobaile Charge ?

  • SANDEEP BERA's picture
    Oct 31, 2017

    i want to know that is it the mobilecharger using buck converter or not?? pls clarify

  • yahaya galadima's picture
    yahaya galadima
    Mar 04, 2018

    good and simple

  • moeez 's picture
    Jun 02, 2018

    what if 2A transformer is used ????

  • Aswinth Raj's picture
    Aswinth Raj
    Jun 06, 2018

    Yes you can use a 2A transformer, it will increase the output current of the circuit. But since 7805 can supply only upto 1.5A you will not be able to draw more than that without damaging the IC

  • Manish Kumar Srivastava's picture
    Manish Kumar Sr...
    Jul 01, 2018

    Plz,tell me how to connect a charger with USB.

  • Aswinth Raj's picture
    Aswinth Raj
    Jul 04, 2018

    Cut the charging cable of any old charger and find the positive and negative wire in the cable and connect it to the circuit.


    However this circuit is only for educational purpose and is not intented to be used for practical applications without any modifications 

  • payam's picture
    Jan 08, 2019

    is the above mentioned circuit unsufficient for a practical use? what else are necessry ? and why

    how can we make our resolution stable enough for example if the input ac voltage changes?

  • Aswinth Raj's picture
    Aswinth Raj
    Jan 09, 2019

    The circuit can charge your phone for sure but is highly un effeceiant. All mobile chargers use Switching circuits. Here a linear regulator with Transformer is used.



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