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Power Supply Board For FREE

Discussion in 'General Electronics' started by Gary Lecomte, Apr 22, 2004.

  1. Gary Lecomte

    Gary Lecomte Guest

    This is a Voltage and Current Regulated Supply with the ability to go
    to down to Zero Volts. It is not super Quality, but Definately good
    for Beginners or anyone wanting a Simple Design.
    So, If interested in a Reasonably Good, but Simple Power Supply
    Project and a
    Chance to Win my Assembled Proto For FREE, This Weekend.
    (Also Mailed Free of Charge to the winner)
    Go to: http://www3.telus.net/chemelec/Projects/Projects.htm

    For Details, Click on the "Power Supply" Project.

    Take care......Gary
     
  2. mike

    mike Guest

    Why would you want to reverse bias a tantalum cap???
    mike

    --
    Return address is VALID.
    Bunch of stuff For Sale and Wanted at the link below.
    Toshiba & Compaq LiIon Batteries, Test Equipment
    Honda CB-125S $800 in PDX
    Yaesu FTV901R Transverter, 30pS pulser
    Tektronix Concept Books, spot welding head...
    http://www.geocities.com/SiliconValley/Monitor/4710/
     
  3. Gary Lecomte

    Gary Lecomte Guest

    Where did I do That? I don't see it.

    Gary
     
  4. Ken Taylor

    Ken Taylor Guest

    Nor do I. I would like to see a few 0.1uF cap's at input and output of the
    reg IC's though.

    Cheers.

    Ken
     
  5. Gary Lecomte

    Gary Lecomte Guest

    Hi Ken, I tend to use 1 uF tantalums as I have thousands of them and
    find they work quite well. But if you wish to Substitute .1 uF caps in
    place of some or all of them, they will work as well, Maybe better in
    RF Situations.

    There are Improvements that can be made, but This is definately close
    to a Minimum Parts count for a supply that is both current and voltage
    regulated as well as the ability to go down to Zero volts. Great for
    the Beginner.

    This design is not totally unique, but better than most I have seen on
    the net.

    My hope is it is Cost Effective and Useful to some of these persons.

    Take care.......Gary
    Take care.........Gary
     
  6. mike

    mike Guest

    This group seems to like "where's waldo" types of exercises.

    If nobody else finds it, I'll post what I think. Maybe I'm wrong...

    Hint: There are only four places to look. How hard can that be? ;-)

    Just curious about the current limit behavior. I'm kinda worried about
    what happens when the input voltage to the second IC drops below what
    it takes to make the chip work. How's the transient response in and
    out of current limit? Try a plethora of load lines and rep rates on
    your transient generator.
    mike


    --
    Return address is VALID.
    Bunch of stuff For Sale and Wanted at the link below.
    Toshiba & Compaq LiIon Batteries, Test Equipment
    Honda CB-125S $800 in PDX
    Yaesu FTV901R Transverter, 30pS pulser
    Tektronix Concept Books, spot welding head...
    http://www.geocities.com/SiliconValley/Monitor/4710/
     
  7. Take a look at what happens when your variable resistor is set to 0.
     
  8. Ryan

    Ryan Guest

    In order for the output to get to 0 V the adj lead must be -1.25 V
    with respect to ground. This reverse biases the cap on the adj lead.
    Use a ceramic here.

    Ryan
     
  9. Ken Taylor

    Ken Taylor Guest

    I'm seeing double today! :)

    Check the spec's for the beast - you should use 0.1's as well as a tantalum.
    Nice pick-up Mike, I'm flat out reading that late at night, let alone
    interpreting! :)

    Ken
     
  10. Ken Taylor wrote:
    [snip]
    Looks to me as if the 1 uF tantalum from the ADJ terminal to ground is
    seeing anything from the max V minus 1.2V, all the way down to neg 1.2V.
    So this cap had better be non-polarized.
     
  11. Gary Lecomte

    Gary Lecomte Guest

    OK, I see, but after 2 days it didn't affect it and a good portion of
    the time it was at zero. In any case, that tantalum, or all of them
    can be replaced with .1 uF caps.

    Gary
     
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