Build two linear power supplies.

Discussion in 'The Projects Forum' started by ScottWang, Apr 15, 2013.

  1. ScottWang

    Thread Starter Moderator

    Aug 23, 2012
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    Hi Dear All:

    I want to build two new linear power supplies, now I already have the power supplies as below:

    1 0~50V/ 2A/4A Linear Regulated Adjustale dual polarity Power Supply
    With output short-circuit protection using relay.
    Base on LM723 and two 2N3055.
    This is a kit that I bought it long time ago, so I have the circuit diagram.

    2. Fiive Fixed Voltages Linear Regulated dual polarity power supply.
    The three fixed voltages that they are series in as ±15V → ±12V → ±9V.
    a) ±15V -- Using 7815,7915.
    b) ±12V -- Using 7812,7912.
    c) ±10V -- Using Six 1N4007. (connected from ±12V).
    d) ±9V --- Using 7809,7909.
    e) ±5V --- Using 7805,7905. (this transformer is stand alone)

    I bought the two transformers as below:

    1. PT-47 (Made in Taiwan)

    Input : AC 110V

    output :

    AC 24V,0,24V ------------ 0.6A
    AC 0,6V,11V ------------- 2A
    AC 42v,36v,0,36v,42v -- 6A
    AC 0,24V ----------------- 1A

    2. Another Transformer (no type number) --

    Input : AC 110V

    Output:

    0,12v ------- 1A
    0,12v ------- 2A
    42V,0,42V -- 5A
    24V,0,24V -- 2A

    The functions of the new power supplies:

    1. Linear regulated dual polarity power supply.
    2. Dual tracking.
    3. Temperature detection and loopback current control.
    4. output short-circuit protection.
    5. 12bits ADC 7-segments LED Voltage and Current Display
    6. USB communication System - Using AT89S52 Can be communicate with computer.
    7. LM317 & LM337 Base with 2N3055 And 2N2955 or MOSFET.
    8. Adding some other functions or using other regular IC.

    I am open my mind to hear any suggestions from you guys.
    Thank you.
     
    Last edited: Apr 15, 2013
  2. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Is it necessary to have it hanging from a PC?
     
  3. #12

    Expert

    Nov 30, 2010
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    When I did the five fixed voltages, I used the L versions because 100ma is more than enough to run most of my experiments, and they smoke less when my mistakes are limited to 100ma.

    Do not try to get more than 3 or 4 amps out of a 2N3055. You will have massive heat problems, even at that level.
     
  4. ScottWang

    Thread Starter Moderator

    Aug 23, 2012
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    Because I already have some independent power supply, the new power is designed for the new measuring experiment.

    I bought a multimeter UT61E, it has Rs232 function, but the capture time is auto setup by the program, the maker didn't announce the control method, they just send the software to run it between the multimeter and computer, so I can't design the software by myself, if I want to design the software by myself that I have to spend more time to figure out how they communicate.
     
  5. ScottWang

    Thread Starter Moderator

    Aug 23, 2012
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    Thanks.
    The circuit that I got it when I buy the kits, the original design that the 2N3055 is designed for 2A, so I keep it in my mind, two 2N3055 just for 4A, one 2N3055 for 2A.

    I would like to using MOSFET to place the 2N3055, but I'm not figure out the good method yet.
     
    Last edited: Apr 15, 2013
  6. #12

    Expert

    Nov 30, 2010
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    It doesn't seem hard from here. Mosfets just use more voltage and less current to run their gates.
     
  7. ScottWang

    Thread Starter Moderator

    Aug 23, 2012
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    Yes, maybe that is not so hard, but I have to try it in the amplifier area, I can't treat it like a switch now.
     
  8. #12

    Expert

    Nov 30, 2010
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    When you can post the schematic, we will check it for proper analog operation using mosfets.
     
  9. ScottWang

    Thread Starter Moderator

    Aug 23, 2012
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    I'm not draw the circuit yet, because I would like to hear the suggestions, maybe that can give me some new ideas.
     
  10. #12

    Expert

    Nov 30, 2010
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    I don't know. Power supplies are about as old as Edison.
    On the other hand, I like to include an adjustable constant current source, or switchable...1ma, 10ma, 100ma.
     
  11. ScottWang

    Thread Starter Moderator

    Aug 23, 2012
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    Thanks.
    The transforemer has some secondary coils, maybe I can use them for different current.

    I have been design a simple adjustable current of the power, but I haven't design the adjustable constant current source yet, switchable...1ma, 10ma, this is useful and easy to do.
     
  12. t06afre

    AAC Fanatic!

    May 11, 2009
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    Huh that sounds more like a design order than a request for help:confused:
     
  13. ScottWang

    Thread Starter Moderator

    Aug 23, 2012
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    Ha ha, that would be my toy not the order from customer.

    I just want to know that how to using two transformers to get more useful functions.
     
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