Search results

  1. redwire

    0-30V Stabilized Power Supply

    Lighty,  do you have the 2N3055's on a heat sink during testing?  Are the 2N3055's touching the PCB?    What is the value of R17?  Have you taken a magnifiying glass to inspect the tracks to be sure there are no shorts?    At 1.7 Amps Q4 and Q5 should be pretty  hot even on a heat sink.  It...
  2. redwire

    0-30V Stabilized Power Supply

    fgrotti,    OUTSANDING JOB  !  Neat and organized,    What is the output?    The front panel looks professionaly done.  What was your process?
  3. redwire

    0-30V Stabilized Power Supply

    Hi lighty, In in my eagle file that you posted  I noticed that you don't have the ground plane filled under the power resistor  (blue outline on left hand side).  In the Eagle program, hit the ratsnest button and it will fill automatically.  Without it filled there are a few connections that...
  4. redwire

    0-30 Vdc Stabilized Power Supply

    gogo2520,   I would not have an objection if you labled this thread "old"  and the other one "new"  or part 1 and part 2.     I started the other  tread when this one was  lost.  It was meant to be a continuation of the original thread.  Having 2 out there  is confusing to new posters.   The...
  5. redwire

    0-30V Stabilized Power Supply

    Noworries2004,      Why don't you test your circuit with only one output transistor without a load.  You don't need  the .33ohm resistor or the heat sink.  you should only have 4 wires.  1) point 7 to  the collector on the  transistor  2) point 8 on PCB to base    3) Emitter output from the...
  6. redwire

    0-30V Stabilized Power Supply

    noworries2004,     audioguru               To isolate the problem couldn't noworries simply remove the output transistor then connect a multimeter to the emitter of the driver resistor- BD139 (PIN Eight) and the other lead on PIN 4( ground) and adjust the voltage pot.  Wouldn't the voltage...
  7. redwire

    0-30V Stabilized Power Supply

    Hi noworries2004.               Knowing that you are using a pcb that has been comercially produced , its got to be the output transistors.  Are you using the BD139 with the metal tab facing you as shown in the pictures on the 1st page.  I guess you are trying this with one output...
  8. redwire

    0-30V Stabilized Power Supply

    Hi miske  Take a look at the first post in this thread
  9. redwire

    0-30V Stabilized Power Supply

    You don't want to parallel the BD139's  it will become a mess.  YOu would need to add resistors to ensure one doesn't hog all of the current just like what is done for the 3055's.  You are correct in that the easiest solution is to change  the 139.  Audioguru would need to comment on the...
  10. redwire

    0-30V Stabilized Power Supply

    If matt09 uses several MJ11016G Darlington transistors instead of the 3055's    then the BD139 should be able to drive the output transistors.   Now he may loose one volt of max output.   And yes R7 would need to be a very low value and large (something like a 0.1 Ohms  25W aluminum housed...
  11. redwire

    0-30V Stabilized Power Supply

    Nice Job, Congratulations.
  12. redwire

    0-30V Stabilized Power Supply

    GrahamG.    I built the original, and at the least 2 revisions.  I didn't build cases for each but I did temporarily test them with a load.      For the 5A version, I would definately mount the rectifier to the case for maximum heat disipation.  The PCB will work fine just use wires to connect...
  13. redwire

    0-30V Stabilized Power Supply

    GrahamG and Holt Look below the message block and you will find     Click on that and you can attach certain files.  Sometimes it will reject certain  formats but if you zip them it is usually not a problem.
  14. redwire

    OOPS I droped my laptop PS in a bucket of water

    Nothing on Ebay ?
  15. redwire

    Design new 0 to 30V power supply.

    I agree.  As noted  above   Providing safe controllable  hardware failures is  not always possible and can sometimes lead to unexpected results.  Having a second line of defense as well as a visual (LCD readout) of the problem in advance (seeing temperature rising uncontrollably,  or how the...
  16. redwire

    Numeric Voltmeter with Lcd Display (need help pls)

    Are you measuring the voltage at pin PA0 or pin PA1?
  17. redwire

    Design new 0 to 30V power supply.

    As long as you are using the ADC on the IC,  why not measure and display temperature of the transistors or other critical parts.  This can be a secondary shut down method if something goes out of wack while in development or evaluation,  but it would give you a visual indicator of the system. ...
  18. redwire

    0-30V Stabilized Power Supply

    Tarkul    Mouser is a large firm located in Texas.  They have plenty  of these chips. 
  19. redwire

    0-30V Stabilized Power Supply

    bugmenot,          I have been meaning to do that for a while and I strongly agree it would be more helpful than searching through 20 pages.  When I first posted, I had some info on my computer at work, some at home and some I had to gather from other posters since the site crashed.      I'll...
  20. redwire

    0-30V Stabilized Power Supply

    PicMaster,  You have other mistakes on your board.    R12 and R11 form a voltage divider.  Your board  seems to have errors in this area. 
View older results
Top