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Transformerless Switch Mode Power Supply Circuit

By Jestine Yong on July 4, 2011

This website was recommended by Beh about "Transformerless Switch Mode Power Supply Circuit". If this circuit/IC can be further improve then in the future we may not need transformer to get the secondary output voltages. Manufacturers could save the cost of not using the transformer and electronic components. The troubleshooting could be much easier too. Please click on the above photo for more information:

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25 Comments

bijoy

July 13, 2011 at 11:51 pm

thank you

bijoy India kerala(gods own country)

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mohamamad jusuf

July 16, 2011 at 9:32 am

Thank you your diagram that I will to make this circuit....

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Amir Mukhtar

July 20, 2011 at 4:12 am

Sir,
Transformerless power supply diagram is useful but please express some more information about to increase power output and voltages upto 36 volts and 1500 mili Amperes.
iam very thanksful to you in this regards.

A student
Amir Mukhtar

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admin

July 20, 2011 at 7:25 am

HI Amir,

It all depends on the ability of the IC and the circuit. If the manufacturer produce many different type of similar ICs as above i don't see why your request cannot be done.

Jestine

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Sagar

August 28, 2011 at 1:25 am

My smps is not working how to check it, solution to repair it

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admin

August 29, 2011 at 9:14 pm

Hi Sagar,

May i know what are the components you have checked? Did you get any supply voltage to the power ic?

Jestine

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- werdan
  
  December 28, 2016 at 10:00 am
  
  Good day! puzzled regarding p/b led TV, it was a/c input with rectifier bridge but output reads 1000 volts with a capacitor 450v/68mf, is it normal, what was the causes of getting more than capacitor rating?
  
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  - Jestine Yong
    
    December 28, 2016 at 3:24 pm
    
    Hi Werden,
    
    If more than a 1000 volt, the cap already blown. How do you test the cap?
    
    Jestine
    
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ali

September 8, 2011 at 1:57 pm

really it was to hard for me to get your website
cause i have alot of questions first of all let me itroduce
my self.iam ali from yemen ihope u heard about it
and working as a photocopiers tech.so pls accept me as a begainner

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admin

September 8, 2011 at 9:15 pm

HI Ali,

You are welcome to this blog.

Jestine

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M Shahbaz khan

November 17, 2011 at 12:23 pm

HI
Dear
I need the chooper circuit diagram of the fixed 24 volt and 6 Amp circuit.
If any one can designe the required circuit so contact with me.
Circuite detail is as below.
chooper circuit diagram
Input voltage 210 to 240 volt AC
Constant 24 Volts DC 6 Amp

Thanks
M Shahbaz Khan

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admin

November 18, 2011 at 5:01 am

Hi Shahbaz,

Sorry i do not such diagram.

jestine

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Leo

November 24, 2011 at 3:15 pm

Transformerless PSU is good for some systems. Those systems that the user cannot touch the conductors...

This type of PSU, as you can see in the schematic, isn't isolated from the high voltage mains. If ever the user touches any conductor while his/her body is in contact with the ground(earth), the user has a very high tendency to be electrocuted.

The transformer on PSU's doesn't only serve to step up/down the voltage, but serves as isolation as well.

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admin

November 28, 2011 at 5:23 am

Hi Leo,

You are right and thanks for the comment!

Jestine

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Mamade Ibrahim Joomun

March 22, 2012 at 11:29 am

Hi Jestine,

I would like to know if you have a circuit diagram for:

Input voltage 50 to 440 volt AC
Constant 5 or 12 Volts DC 100mA.

Thanks

M I Joomun

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- Jestine Yong
  
  March 22, 2012 at 8:56 pm
  
  Hi Mamade,
  
  Sorry I do not keep circuit diagram.
  
  Jestine
  
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GIrma Assefa

July 14, 2012 at 8:34 am

Hi jestine i am from addis ababa Ethiopia .
I am reading ur news letter & bouneses it is very important to me & i use it as manual thanks to u especially about LCD repairing & power supply throubleshooting i thanks u from my heart .mr.jestine in my country there no on line bussines opportunity that is why things littele dificult to buy ur books & diffrent testers.I trying via USA to communicate u and send money to u well send me the thinks which i need.
Thanks Jestine keep intouch Girma Assefa
Electrical & hardware Engineer

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- Jestine Yong
  
  July 14, 2012 at 9:43 pm
  
  Hi Girma,
  
  You are welcome and in fact you can use money gram services to send me money to buy my products.
  
  Jestine
  
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Rahul

October 7, 2012 at 1:13 am

Sir Please Tell me about efficiency of the above main circuit.

& please describe the efficiency calculation & also the power factor & ripples calculation... Thanks.

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- Jestine Yong
  
  October 8, 2012 at 11:05 pm
  
  Hi Rahul,
  
  I suggest that you email the owner in the link below for more information:
  
  http://www.circuitstoday.com/transformerless-switch-mode-power-supply-circuit
  
  Jestine
  
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dbgrg

December 18, 2012 at 1:57 am

hi justine Young,
I want to construct 12 volt power supply with auto cutoff.but how to start.please help me

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- Jestine Yong
  
  December 18, 2012 at 6:42 am
  
  Hi Dbgrg,
  
  Sorry I'm not into electronics design thus I can't give any advice on this.
  
  Jestine
  
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raymundo saura

October 19, 2013 at 5:10 pm

Great info thanks and GOD bless

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Gurpreet

July 31, 2015 at 3:04 pm

Hello Mr. Yong

Thanks for sharing information with us.

Thanks
Gurpreet

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- Jestine Yong
  
  July 31, 2015 at 9:34 pm
  
  HI Gurpreet,
  
  You are welcome.
  
  Jestine
  
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