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  1. P

    Design new 0 to 30V power supply.

    What about 2 x 6800UF 50V caps These are new_design_psu.pdf
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    Design new 0 to 30V power supply.

    I did do that in the end I reduced the 39V zener to 36V and used a 4.7V zener and with no load the pot now can go to 0% and still obtain the voltage out, If  used 33V zener with 4.7V you don't obatin the full voltage out, I placed the current porbe on the output it reads 0.001A with the pot set...
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    Design new 0 to 30V power supply.

    I have added the -9 supply and to me makes it worse, well in sim mode I now have to take the current pot to 8% before I get a voltage instead of 2%, Unless some thing else needs altering.
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    Design new 0 to 30V power supply.

    I've start to look at part and The supplier I use I can't get the 22000uF caps but can get these 10000UF 50V 105C HE SERIES SNAP IN RC  Rapid part number  11-3165 from here...
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    Design new 0 to 30V power supply.

    Sorry this was after the new year party, I will explain better now Herro the +88.8 is greyed out when the simulator is not running(this is there default state), Once I start the simulator they then read the correct voltage. I've re-looked at the drawing and made the correct modifaction to my...
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    Design new 0 to 30V power supply.

    Yeah this is for testing purpose only, It was the only way that I could get to simulate it because with the mosfet in there i was only getting max voltage out and no variation in the output. I know that simulators can sometimes play up causing all sorts of problems let's just hope this does not...
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    Design new 0 to 30V power supply.

    I'm simulating mine in ISIS and everything seems to work OK, To get it to Sim correct I've had to remove M1 and replace with relay has I could not alter the output voltage has the way it is drawn it always stayed at max output voltage, The way it is set up at the moment to me is working great...
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    Design new 0 to 30V power supply.

    The velleman power supply I have got had  2 pots that you had to calibrate min and max, the had to be set for about 2-6ma and the max was for 5amps, I suppose that's how they got around it so when the main current limit pot turned turned to zero the calibration pot prevented the volts from...
  9. P

    Design new 0 to 30V power supply.

    I would say limit it to 30V has the extra 3 volts woudl not make that much difference I totaly agree has it's simple and an easy to obtain the part, Cost does play a apart in slightly but it want want to build a quality PSU then cost does not matter to much, After all if you had
  10. P

    Design new 0 to 30V power supply.

    Sorry on reding it back I should of not asked that question really I did not mean to sound to be rushing.
  11. P

    Design new 0 to 30V power supply.

    It was only a thought has they used that in a Velleman 0-30V 0-10A psu which I did have one and never seen the voltage drop has it will be has quick has the mosfet, But if the mosfet is the better way to go then that's the way to go how long do you reckon before we can build one for real and...
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    Design new 0 to 30V power supply.

    I know I would of used 10bit PWM myself, Just has a thought instead of using a mosfet to switch the higher volatge what about a relay instead Like the drawing below, Once the output reaches 12V the relay kicks in the higher voltage
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    Design new 0 to 30V power supply.

    Looking and studying the drawing more I can now see that M1 acts as a switch silly me. I understand now you are correct in saying that I've got resistors that used to dissipate the heat. I will see if I can find any more info out, I did build the circuit on a test board so that I could control...
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    Design new 0 to 30V power supply.

    Has I understamd this was not a very good power supply, I've never built it but others copied it and they removed there design off there web sties saying it was unstable, but you may be to understand it better than me I love this topic I'm learning so much from you guys it's mind blowing...
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    Design new 0 to 30V power supply.

    I can help out there, I have the code working to a degree, I send out a smooth stable volatge of 0-5V with a coarse and fine settings, This can be sorted out once we have a working power supply, we can just include it on the PCB this way people can a have a choice what they like to build. Yes...
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    Design new 0 to 30V power supply.

    It's looking vey nice,  ;D What op-amps are you thinking of using ? Where does IOUT go that feeds the op-amp ? Aslo which one aught to do the job 15 + 15V(sorry I put this down has 30V) or the 12+12V ? Has for the delay I would think it should be fast enough to trip If I understand it correct...
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    Design new 0 to 30V power supply.

    I'm willing to give it ago and help in testing, and help out with the PCB design if needed, I've got most of the parts but depending what parts are used, I have a 30V 600Va transfomer and a 12+12V 300Va tansformer, The only parts I may need to get are the op-amps
  18. P

    0-30V Stabilized Power Supply

    I thought I'd ask the experts on here about these specs are they any good ? Output voltage variable from 0v to 30V. - Fine tuning over 1V - Output current limiting device infinitely variable from 0 to 5A. - LED (light emitting diode)-indication of current limitation - Output current: 5A. -...
  19. P

    0-30V Stabilized Power Supply

    Thanks for that I did spot that one, This has now been corrected, Aslo ZD3 has been reomved has it is not needed, Thanks Picmaster
  20. P

    0-30V Stabilized Power Supply

    Sorry that's my fault I missed those 2 values I can see that they should be 2K2 and 82R, Thanks for pointing that out, I will recheck the rest of the values, I presume that everything else is ok ? PCB is about 80% laid out and routed I will post as soon has it is done. Thanks
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