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Cheapest SMPS Circuit Using MJE13005

The explained circuit in this article is probably the simplest and the cheapest, since it employs minimum number of components and the making of the circuit is very straightforward.


Generally SMPS topology involves some fixed standard stages and criteria. Thgey may be listed in the following manner:

The first stage which is the input stage incorporates an obvious mains rectifiers stage, followed a few important protection components.
The above protection components may be in the form of an MOV , or an NTC or both of these for suppressing high voltage transients.

The next stage involves a mosfet based IC in conjunction with the primary of a small transformer for generating the required oscillations.

The IC is normally a state-of -the-art chip having many in built features and abilities.

Further on the secondary of the transformer is clamped with the mosfet IC through a optocoupler which takes the responsibility of controlling the output voltage to a predetermined fixed level.

However the proposed circuit of a cheapest SMPS circuit is rather free from all these complications and employs a very simple configuration.

The input does not involve any protection, which is rather replaced with the snubber network around the transistor. Moreover the rugged MJE13055 is assumably strong enough to take on most the situations.

The two winding on the primary side are so arranged that on switch ON the circuit immediately starts oscillating at around 100 kHz.
The secondary winding typically decides the output voltage and here no optos or zeners are introduced for the sake of simplicity.

Having said that, the circuit  may be considered quite crude and therefore in some way might be vulnerable at some point of time in the long run.




Here's another identical  simple 220V SMPS circuit design you would like to investigate:




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  • 47 comments:

    1. Hi Swagatam,

      can you list all the components? its hard to read in the circuit diagram.

      thanks and regards,

      ReplyDelete
      Replies
      1. Hi,

        I have updated the diagram, please check it.

        Regards.

        Delete
      2. Hi,

        Thanks a lot. Now it is clear.

        Regards,

        Delete
    2. Very interesting circuit idea for hobbyists! thanks in advance!
      I want to know some things--
      1) Output power rating of this circuit- how much mA or Amps ??
      2) please specify the details of the transformer- winding details?? can it be home made with a ferrite rod or torroid ferrite core? plz plz give the wire details!
      3)how much stable this circuit with voltage surge/fluctuations? input voltage range??
      4) can the same circuit design be made with low current Transistors like 13001/13002 etc for making low wattage/power charger or dc power supply?
      5) in place of diode 5402, can two or more IN4007 may be used in parallel?

      ReplyDelete
      Replies
      1. Thanks!
        The circuit was taken from some other website, I don't remember the exact location...roughly I can say the following:
        1)Power will depend on the SWG of the sec winding, and the inductor size, but cannot exceed above 2amps.
        2)I cannot say about the transformer winding detail, you may consult a professional coil maker. The inductor definitely needs to be done over Etype cores.
        3)This circuit is crude, so cannot guarantee regarding output standards.
        4)13001, 13002 can be used.
        5)1N5402 is more safe and a better option than two 1N4007s

        Delete
      2. Dear Sir,

        i am working on the 15V SMPS design, as i am interested inyour design Ckt so wanna make 15V SMPS on the same.kindly let me know how can we increase the Output voltage & current on this design as per my requirement.

        Delete
      3. Dear Ashu,

        Normally by increasing the number of secondary turns results in a proportionate increase in the output voltage, while increasing the thickness of the wire results in an increase in current.

        It's better to use parallel connected wire of two or three instead of using a single thicker wire, for increasing current.

        Delete
    3. Thanks for the circuit. But it lacked a rectifier Capacitor at the output of the diode bridge.

      Quoc Dang

      ReplyDelete
    4. Thanks, yes you may add it for better response. A 10uF/450V will do.

      ReplyDelete
    5. Is it possible to make the transformer without a core???

      ReplyDelete
    6. please explain the working of this circuit @Swagatam Majumdar

      ReplyDelete
      Replies
      1. I have explained it in the article roughly.

        Delete
    7. Hi!Thank You for this,it is really simple!Do You maybe know some other SMPS with bipolar transistors?I have a lot of bipolar switching NPN transistors (BLD128,D13009...) and i would love to use them and make SMPS.Most of circuit i find use MOSFET and/or IC.Please help me if You can.Thank You and all best!

      ReplyDelete
      Replies
      1. Hi! thanks!

        Presently I do not have a suitable circuit as per your requirement. if i find one will surely update it her for you...

        Delete
    8. I have constructed the circuit.checked well. unfortunately MJE 13005 is heated up heavily. No output is detected.

      ReplyDelete
      Replies
      1. The transformer is a critical part in the circuit, it might need modifications or corrections.

        Delete
    9. Hey Guy!
      Which is the power for the 47 Ohnms resistor?
      Thx!

      ReplyDelete
    10. Hi sir

      How make the transformer which you above explained.

      Thanks
      Kumar

      ReplyDelete
      Replies
      1. Hi Kumar,
        I am sorry, I don't have the exact specifications for the transformer

        Delete
    11. In this circuit Please tell me which Component you used for high frequency switching?

      ReplyDelete
      Replies
      1. the transistor and the associated components.

        Delete
    12. don't use 1N series at the output such diodes used for Low frequency rectification....u have to use fast recovery diode like UF5402(ultra fast diodes)...switching frequency of smps is in terms of kHz..mail me if you want efficient and cheap smps circuit design using BJT and mosfets..arspc8@gmail.com

      ReplyDelete
    13. can you explain the working please... i thought that the reservoir cap shud be between the ground and vcc of the primary.(hi voltage section i mean).. but here its btween the vcc and the transistor... :/

      ReplyDelete
      Replies
      1. a filter capacitor may be added after the bridge, the capacitor you are referring to has a different function and is also crucial.

        Delete
    14. sir i want 24 volt 1 amp ckt in above ckt some suggestion plz..
      thnks

      ReplyDelete
      Replies
      1. Khodal, the above designs are not confirmed ones, instead you can try the following , but you will need to make a PCB for this:

        http://homemadecircuitsandschematics.blogspot.in/2013/10/12v-24v-1-amp-mosfet-smps-circuit.html

        Delete
    15. Hi,regards.i m designing a 5v 1amp smps can u pls help me to get some idea.i want to charge samsung phone.i opened a samsung charger it consist of 13003 transistor and one 5 pin smd very small part to drive 13003.it marked rf27.in another charger it marked in30 and another one marked in70.can u pls help me to make a fast charger

      ReplyDelete
      Replies
      1. Hi, I could not find any info regarding the devices in30, in70, so can't suggest much, rather you could try the following design for getting identical results:

        http://homemadecircuitsandschematics.blogspot.in/2014/02/220v-smps-cell-phone-charger-circuit.html

        Delete
    16. Hello sir,

      I hav noticed the 2nd schema, that it has a bridge rectifier both in input and output, it is in wrong configuration, and also in the collector of the transistor, the diode is reversed biased. Therefore this circuit wont work,

      Sorry, just trying to help.

      ReplyDelete
      Replies
      1. Hello khema, thanks for pointing it out, both the circuits were taken from some other site, these are not verified by me....yes the bridge configuration looks in the opposite direction for the second diagram, not sure why it's been configured in that way, I found it in one of the forums.

        Delete
    17. can you please give me the detail of transformer

      ReplyDelete
    18. can you please give the detail of transformer winding.

      ReplyDelete
      Replies
      1. you can make it with the help of the inductance values given in the diagram...

        Delete
    19. Hi I am Khurram Mateen kindly send me winding data

      ReplyDelete
    20. Sir, i want to make smps with +12V, gnd & -12V. Is that possible? & if so, how to build the circuit? Plz provide me the circuit diagram...

      Regards,
      Mandar

      ReplyDelete
      Replies
      1. Mandar, you can try extracting a center tap out from the secondary winding and get the required dual voltages .

        Delete
    21. what is the output of above circuit, can be arjusted for 5v, 9v and 12v

      ReplyDelete
      Replies
      1. yes you can do it by using 78XX regulator ICs

        Delete
    22. Hi Swagatam,

      I have a query regarding switching frequency..how can we select or calculate the freq. in flyback topology (upto 100W ) SMPS? I mean to say, in above ckt. which component is used for generating the switching freq.?

      ReplyDelete
      Replies
      1. Hi Maddy, i can't suggest the formula immediately since I have not yet investigated the circuit deeply... but it's the base capacitor/resistor and the 47uH winding which are basically responsible for the frequency value..changing the value of any or all of these elements could cause variations in the frequency....

        Delete
      2. Can u tell me, how to design transformer for smps?

        Delete
    23. How many turns are needed for primary and secondary? And can i use transformer which used in phone charger directly?

      ReplyDelete
      Replies
      1. turn numbers are shown in the second diagram, click to enlarge it.

        no you cannot use the phone charger trafo directly.

        Delete

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