Bench Power Supply 0-25v @ 0-5amp

Author admin    Category Work Bench Tools     Tags , , ,


This project is like the one that all of you must have done in electronics.  I took the idea from Circuit Cellar. The original power supply provides an output of 2.5-15V at 500mA. This circuit will provide 0-25V at 0 to 5A. You will see there is a lot of modification to achieve this.

This is my second version of this power supply, the first one was made with mosfet who need a higher voltage on the gate I had to use a higher input voltage and because of this there was a lot of heat generated for nothing.  This version work with transistor and it's much more better. 

    I will explain you some part of this power supply.  First you must find a transformer which can handle 24VAC at 5A and one with 6.3VAC at 100ma.  I use 2 transformator to have 2 DC level 30V and 40V. The 30V Power the high current for the output and the 40V power all the rest of the circuit.  The LT7013 opamp is split in 2 function, the part A is the voltage control and the part B is the current control both opamp output is connected together via diode so the one who output a lower voltage win on the second, so if you set your voltage to 10V and your current to 1A and you short your ouput the current part will pull down his output and the voltage will drop.  The current part use a very nice component the ZXCT1009 that work like a current mirror.  it will generate a current proportionally the the one who pass in the sense resistor, this current is pass in the pot R8 who convert it in voltage.  The output have many transistor because the opamp can't give a lot of current, and note that the resistor R23 is very important, this one will protect your output transistor from a output short circuit "transistor explosion is faster than the current sense".  If you build this supply you will be impress how fine it's work.

    I also connect to this power supply a LCD to inform you of the set point for voltage and current, plus the current voltage and current.  It's done with a small ATMega32 with 4 A/D input to received the value from the power supply and with some simple calculation it display those value.




  • Output Voltage adjustable from 0 to 25v
  • Output Current adjustable from 0 to 5amp
  • Digital reading of set points for current & voltage and output current & voltage.
  • No need of multi tap transformer or center tap transformer
  • Short circuit protected
  • Very low cost



PowerSupply Schematic

Graph LCD Schematic

Graph LCD Source Code

123 Comments to “Bench Power Supply 0-25v @ 0-5amp”

  • Frank Huang April 9, 2010 at 4:39 am

    Cannot get PowerSupply Schematic !
    Would you send it to me ?

  • admin April 9, 2010 at 1:07 pm


    I just correct the link retry to download.


  • emt training May 1, 2010 at 4:43 am

    Valuable info. Lucky me I found your site by accident, I bookmarked it.

  • ppt May 16, 2010 at 8:05 am

    Can you post some photos of LCD display when working?
    Best regards!

  • admin May 16, 2010 at 3:32 pm

    I will try to do your request this week, I’m very busy

  • Bruce May 21, 2010 at 10:11 am

    I will try to do your request this week, I’m very busy

  • admin May 21, 2010 at 1:09 pm

    I just had the picturel, go in the powersupply gallery

  • ppt May 22, 2010 at 1:15 pm

    Thank you!
    Looks great !!!
    Best regards!

  • ppt May 24, 2010 at 5:25 pm

    Can you please say what  type of  LCD display is used? Seems like not standart LCD…

  • MicroSyl May 24, 2010 at 6:42 pm

    It's a graphic LCD of 128×64 pixels, with a SED1330 as controler

  • fake May 24, 2010 at 7:37 pm

    Bench Power Supply 0 25v 0 5amp MicroSyl MCU Electronics projects best post. I has been collection in my blog. 2010/06/06

  • ppt May 25, 2010 at 3:47 pm

    Seems be impossible to get this type of LCD at our location. Do you plan write code also for other
    type 128×64 graphical LCD (for example BOLYMIN BG12864AYPLHn)?

  • admin May 25, 2010 at 4:19 pm

    No, but you can make your own,  You can do it with a simple text LCD


  • Anton August 27, 2010 at 2:04 pm

    MCU_SCH.sch  file does not open

  • ppt September 12, 2010 at 6:08 am

    Hi ,
    What transformer is used for 40V level ?You wrote  that 6,3V in text and 4VAC in schematic so what
    is right value ?
    Thank you!

  • MicroSyl September 12, 2010 at 2:09 pm

    6.3 will do the job

  • Bench supply with current limiting - Hack a Day October 8, 2010 at 2:21 pm

    [...] is a bench power supply with adjustable voltage and current limiting. [Sylvain's] creation can regulate 0-25 volts while sourcing 0-5 amps. Current limiting is a nice [...]

  • iklln6 October 8, 2010 at 4:35 pm

    the MCU_SCH is  a protel schematic.  you'll have to use the .png to make your own schematic if you're trying to open it with eagle

  • admin October 8, 2010 at 5:26 pm

    It’s done with protel, not in eagle

  • admin October 8, 2010 at 5:26 pm

    the 6Vdc is add to the main power check on the sch

  • Stan October 8, 2010 at 7:43 pm

    Hi! Your PSU looks really good. I am so tempted to build it. Would you publish Part List and PCBs? Thanks

  • admin October 8, 2010 at 7:46 pm

    All I publish is already on my web, I don’t give anything more

    Sylvain bissonnette

  • Bench supply with current limiting | secureXsystemblog October 9, 2010 at 1:24 pm

    [...] is a bench power supply with adjustable voltage and current limiting. [Sylvain's] creation can regulate 0-25 volts while sourcing 0-5 amps. Current limiting is a nice [...]

  • sanjay October 9, 2010 at 2:18 pm

    I wonder why you used a switching transistor (D44VH10) for the pass element, when a linear transistor (e.g. MJ15003, 2N3773 etc) would be much more appropriate ?

  • admin October 9, 2010 at 3:00 pm

    It will make the job too like a 2N3055, that was what I have in my lab and it’s work too

  • DIY Digital Bench Power Supply - Hacked Gadgets - DIY Tech Blog October 10, 2010 at 12:51 am

    [...] bench power supply is a must for any hardware tinkerer, this DIY Digital Bench Power Supply by Microsyl is a bit high end and much more than you need but in the end you will have a great [...]

  • Jeroen Jacobs October 11, 2010 at 7:52 pm

    I'm very tempted to build the power supply.
    However, I have a question.
    How do you get a DC level of 43V DC out of D6 while the input level is 6.3VAC?
    Because when I calculate 6.3VAC to DC I get: Vac *sqrt(pi)=DC –> 6.3Vac * sqrt(6.3V) = 11.17V
    Could you please clarify?

  • admin October 11, 2010 at 9:17 pm

    My transfo was 6.3v with a center tap, I use the centertap for my low voltage

  • Jeroen October 12, 2010 at 10:06 am

    OK, thanks for the answer.
    I have one more question:
    Why is R26 (160ohms) connected to the output of the 7805?
    Thanks in advance!

  • admin October 12, 2010 at 2:05 pm

    To give the minimum load for the 7805

  • Joe Lotz October 13, 2010 at 8:35 pm

    Nice project! A benchtop power supply is a must for any electronics geek. You can start small for beginners or go big for advanced geeks, like you did.
    I like the large LCDs. It is a nice modern touch.

  • Shined October 17, 2010 at 11:36 am

    Hi Sylvian,
    I appreciate you have put a lot of work into this and I am need of a bench power supply of this capability, I'm relitively new to electronics and some things I can identify easily and others not, I appreciate that you will not make changes for people and I respect that; however would it be possible to get a BOM file for your project, this would help me an aweful lot in obtaining parts or replacement where parts are not available here. Oh BTW more than happy to make a paypal donation if you can help me out.
    Keep up the good work.

  • admin October 17, 2010 at 3:13 pm

    Thanks for your good comment, but what is on my blog is only personnal projects and not kit for sale, I don’t have time to make documentation of bom


  • Shined October 18, 2010 at 2:48 pm

    Thanks for the response Sylvian, I was hoping to get myself a lab supply together for a project I'm working on thats why I was after a BOM over here where I live in New Zealand I'm out of a job at present as the Earthquakes we have had wiped out the company I worked for, I was using learning electronics and development of my own project as an escape from having to think about it. I looked at buying a Lab supply here but they are about 900$ NZ + TAX or about 600 Euro depending on where you live, On my present income thats like 3 years worth of saving.
    Could you at a bare minimum supply me with details of the transformers you used, I did a little reading on the subject and found there are all sorts of details like core, single tap, double tap, number of outputs at x V to take into account, If I had the info as to what make / model they were I would probably be quite set with them and your schematic.

  • MicroSyl October 18, 2010 at 2:53 pm

    Ask your question and I will make the best I can.  Part like transfo was taken from old equipment.

  • Two apples in a pod and that other guy » Blog Archive » power supply October 18, 2010 at 11:30 pm

    [...] supply T J I take it this is mostly for you engineering experiments. T yes this may be cheaper than [...]

  • Shined October 19, 2010 at 8:23 am

    O.K so there are two transformers, I am presuming both are 220-240vac with a 10a max draw but on the output side for the 10amps how many taps are there and the same for the smaller supply?
    Basicly Im trying to figure if either of your supplies are dual output and you are only using one of the output taps or if there is only one output from each transformer for VAC and Current combined. I ask because all the transformers I can get here seem to have two even taps so if its 48v its 2 x 24v and I don't know if this would make any difference in your design. I.E because there maybe two as opposed to one I may only get 1/2 the current each.

  • Bob Andersen November 9, 2010 at 6:00 am

    Awesome post mate.

  • Felixls November 23, 2010 at 3:14 pm

    Hi, very nice your power supply, I recently completed a similar but using a PIC 18F2550 microcontroller

  • Cristi November 29, 2010 at 8:39 pm

    Great work you have done. Thank you for posting it. 
    What can i use instead of the zxct1009? Is there a way to get de .sch and .pcb files?

  • admin November 30, 2010 at 1:34 pm

    I don’t know parts that can replace the zxct1009, maybe with some research you can find one, I don’t give any other files


  • Thomas December 4, 2010 at 6:20 pm

    I,m a novice at this kind of electronics. But i realy like to build this bench power supply.
    I already have a stabilised 33vdc power supply. Can i use it with your version of the power supply.
    If U have time could you make a drawing for me?
    Kind regards
    Thomas brinkmann

  • admin December 4, 2010 at 8:13 pm

    No I don’t have time and it will not work, you need all the parts in this supply


  • admin December 29, 2010 at 7:24 pm

    10 amps should be good

  • Nathan Reichenberger January 26, 2011 at 1:38 am

    Hi, im a college student looking to build one of your power supplies. I have been looking through your schematics and am wondering if you by chance have a parts list generated. I would very much like to produce one of these but am having some issues following the schematics. If you have a bill of materials atleast for the electronics, i think that may help. Thank you for your time.

  • admin January 26, 2011 at 3:15 am

    Go a head and give me the result!

  • admin January 26, 2011 at 3:16 am

    I don’t have anything of those

  • prendre credit January 29, 2011 at 4:10 pm

    Hua! A beautiful piece of equipment!

  • Dimitar February 1, 2011 at 11:28 pm

    nice project :)
    I can't understand how is it possible to work the current limit when the output voltage is under 5V ?

  • admin February 1, 2011 at 11:30 pm

    I don’t really know but it’s work

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Please note

All my source codes were taken from my personal projects.

Everything is for your information only. The C/C++ codes have been written
with ICCAVR. You can find the header and source CRT files by downloading their compiler.

All is for your information and everything is AS IS without any warranty of any kind. No other files are available and I don't make any modification for any body.



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