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  1. C

    0-30 Vdc Stabilized Power Supply

    Yet another question to you gurus ::) Have a look at the attached image ... is this circuit for the 2nd transistor correct? Which values should R23 and R24 have? Should I use one variable resistor? Thanks.
  2. C

    0-30 Vdc Stabilized Power Supply

    Hehe :P If the author's heatsink is on this picture: I think my heatsink is bigger ;) Ok. I'll see. Maybe I'll use a fan. My trafo has multi secondary. So I could use the 12V secondary to power the fan. Is it for a fan enough to put in 2 diodes? What is a real value for my heatsink with 2.4...
  3. C

    0-30 Vdc Stabilized Power Supply

    I think it is not possible to cool this thingy with passive heat sinks. Please answer my question http://www.electronics-lab.com/forum/index.php?board=15;action=display;threadid=1022;start=0;boardseen=1 about heat sink specification, too ...
  4. C

    0-30 Vdc Stabilized Power Supply

  5. C

    What is K/W from heat sinks?

    What is the heat sink specification K/W? K => Kelvin? W => Watt? What can I do with this value? What a value of 2.4 K/W tells me from the heat sink? Do it grows hot 2.4 K per each heat watt or what?
  6. C

    Always notifications of replies ...

    I always get notifications about a reply but I have not marked the option to get notifications. I've done it in older posts in the same thread but not in the later ones. The reply is to one of my posts without this notification option. Is this a strange behavior of this board? So to say ...
  7. C

    0-30 Vdc Stabilized Power Supply

    Why the 2n3055 produces so much heat in this PSU? I've another 13.8V 10A PSU with two 2n3055 and a similar heat sink. I remember that I can pull out 8A without burning my fingers at the heat sink. How hot is the junction when the case of the part has about 130 degrees?
  8. C

    0-30 Vdc Stabilized Power Supply

    I use the 24V secondary of a 75VA trafo. Both 41.5V. Specified max. of TL081 is 36V. Is there a simple pull out and put in replacement in DIL8 with higher max. ratings? 1.75V 3A => 130 deg. C 4V 4.3A => I switched it off at 175 deg. C Should buy an heat sink ... 14V 4.3A => 120 deg...
  9. C

    0-30 Vdc Stabilized Power Supply

    We are talking about the same circuit ... and you are right but misunderstand me. I've never been talking about voltages across resistors. I've simply measured the output voltage and current of the PSU to know the load. Thanks for the hint with R7. My thingy is finished ... some technical...
  10. C

    0-30 Vdc Stabilized Power Supply

    No, it's R1 and it is the output voltage. But I understand that the problem is not the output power. So the temperature will be constant at about 40 degrees C. I think it is too "warm". Ok, I know that a current meter is connected in series. I will connect it in series but in parallel to the...
  11. C

    0-30 Vdc Stabilized Power Supply

    Ok, my PSU is nearly finished... and what I've tested works fine. I've used a "Lochrasterplatine" (don't know the English word for the boards with many holes). Tomorrow I'll use some car lamps to test the maximum current. I think I will change the R1 resistor to a 4W version. The 1W version has...
  12. C

    0-30 Vdc Stabilized Power Supply

    Can anyone please list all the parts should be changed to be safe? Perhaps with a short description why it should be changed. I am a newbie and after reading the 8 pages of this thread I am a bit confused. I've read something about exploding C7... Is it only a problem of one guy doing something...
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