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  1. morpheous87

    0-30V Stabilized Power Supply

    I've changed the resistor with 47R then 51R also 68R. But there isn't change. I've made completely new board and I have the same anomaly. Both boards works same. This is not so big problem, but it's kind of annoing.  Any suggestions?
  2. morpheous87

    0-30V Stabilized Power Supply

    May be there is something wrong with U3 oamp. I'll try first with a new one, then increasing the resistor's value.
  3. morpheous87

    0-30V Stabilized Power Supply

    So, what value should I use, 68 ohms or ?
  4. morpheous87

    0-30V Stabilized Power Supply

    So, will help only increasing R17(R16) value or I need something more?
  5. morpheous87

    0-30V Stabilized Power Supply

    How exactly to null it? I'm using PicMaster's schematic and there isn't R17. What value it should be?
  6. morpheous87

    0-30V Stabilized Power Supply

    Are there some safety measures for shortening the +/- outputs of the PSU? Also where is apropriate to put a fuse before the regulator and how much A to be? And one more question. The Voltage regulator is working perfect. The current regulator also work, but when the potenciometer is nearly at...
  7. morpheous87

    0-30V Stabilized Power Supply

    I did the schematic, and it works fine. Now I'm going to make another one with aim to make +/- power supply. What I have to do for that, should changes have to be made on the board?
  8. morpheous87

    0-30V Stabilized Power Supply

    For what purpuse are the 3 trimpots? For what ajustments? And is there a way for fine ajustment of the Voltage and Current.
  9. morpheous87

    0-30V Stabilized Power Supply

    This is PicMaster's PCB. I have a question about the PDF. The white print on page 3 and the PCB connection on page 6 aren't same. The parts names and their places are different. I think the white print on page 3 is the correct one, but am I right? EL_power_supply.pdf
  10. morpheous87

    0-30V Stabilized Power Supply

    I didn't want to use 2N3055 because of the TO-3 package. I'm not familiar with it, and I don't know how to connect it. As I saw the collector is the steel case. So, should the steel case be separated from the heatsink or not, and how to connect it(especially collector)? The BD139's heatsink...
  11. morpheous87

    0-30V Stabilized Power Supply

    My aim is only to check the boards, if they work I'll take the nessessary transformer.
  12. morpheous87

    0-30V Stabilized Power Supply

    I want to ask, can I meke the circuit and use a transformer (for example 22V) just to try if everything is OK with the board. And after that to order the transformer which will be used. Is that possible, and if is, what to expect from the circuit to be sure all is OK.
  13. morpheous87

    0-30V Stabilized Power Supply

    I'm going to do this PSU in 3A version with 30V 250VA transformer (with an idea for +/- PSU). So I have some questions before i start constructing it. How big should be the heatsink fot the TIP3055 transistros, and should the BD139's heatsink be separated from TIP;s one? Should the heatsink be...
  14. morpheous87

    0-30V Stabilized Power Supply

    How much VAa should be the transformer for 2x5A power supplies?
  15. morpheous87

    0-30V Stabilized Power Supply

    It would be nice to have a 5A ready for etching PCB.
  16. morpheous87

    0-30V Stabilized Power Supply

    So, the PicMaster's PCB need a little change for the third transistor?
  17. morpheous87

    0-30V Stabilized Power Supply

    What's the difference betwenn 3A and 5A projects. Something in the elements or the transformer?
  18. morpheous87

    0-30V Stabilized Power Supply

    I printed the PCB from PicMaster's file, I think it should be mirrored. So I opened it in Photoshop and mirrored it. Than save it like PDF. Today I printed it, but it's with smaller size. My ask is, should the PCB mirrored, and that size shoud it be. Or just give a ready printable file. Thanks.
  19. morpheous87

    0-30V Stabilized Power Supply

    In PicMaster's scheme are used 1x12000uF 63V capacitor or 2x6800uF 63V capacitor. Can be used something smaller or on lower voltage? There ones cost much, and hard to find.
  20. morpheous87

    0-30V Stabilized Power Supply

    So there isn't problem if 200VA is used. I know that it costs more, but ony that one I found, for now. Thanks!
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