Current Regulator

Discussion in 'The Projects Forum' started by Umer_Farooq, May 8, 2010.

  1. Umer_Farooq

    Thread Starter Member

    Mar 6, 2010
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    i am design a digital current regulator using transistor circuit or ic regulator please help me and define this regulator use after voltage regulator or pre voltage regulator the lm338 use as voltage regulator
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    If you have designed any then show the schema.

    I have an advise for you don't take me the wrong way.
    Every time you come up with something and always ask something without providing enuf info from ur part.
    If you want to do something then first show us what you have, tell us what you did.
    If you have no knowledge on digital electronics then what good will it do if we give you a circuit, as these things are not simple.
    We cannot indulge in trouble shooting a circuit that is limited with ur knowledge.

    First find a circuit. google is ur friend or go through this forum, find something for god sake. We will not spoon feed you, as we are not here to hand out circuits for everyone that are too lazy to do a simple search.

    Time after time I see most of you from India who are studying electronics demand for circuits they have no Idea about. If you cannot use what you are studying then what is the use of studying, do something useful for a change.
    In this world no one will do for you what you do not do for ur self
     
  3. VoodooMojo

    Active Member

    Nov 28, 2009
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    yeah, what R!f@@ says!

    read the part of the datasheet of the LM338 that details current regulation
     
  4. retched

    AAC Fanatic!

    Dec 5, 2009
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    Ouch. You guys hurt.

    What is the END result of the circuit?
    What needs the regulated voltage and current?
     
  5. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    No retched, seriously.
    I really get fed up with some people. They don't do any work, gets on a forum and says I need this, I need that.
    It's OK if at least the do their homework for a change
     
    mahammadmahdi likes this.
  6. Umer_Farooq

    Thread Starter Member

    Mar 6, 2010
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  7. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    From the responses you see that you were getting help quite a lot.
    Opening a new thread on the same topic won't help.
    better continue on existing threads.
    Don't hope for instant reply.
     
  8. retched

    AAC Fanatic!

    Dec 5, 2009
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    Umer, I read one of your other threads, and SgtSookie explained the world to you.

    What is the part that is confusing you?

    Do I regulate Voltage first?
    or
    Do I regulate Current first?

    If that is your question, the answer is
    Voltage first, then current.

    The current regulator will be happier with a regulated voltage to work with.
     
  9. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Retched, is this personal.
    I understand wookie as I read one of Sgt's post on how he got to use the name.
    But Sookie? what the heck is that. :D
     
  10. retched

    AAC Fanatic!

    Dec 5, 2009
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    SgtSnookums would have gotten me more push-ups than I can handle at this point in my life. So I had to take what I could get.

    (Just kidding Sarge.)
     
  11. Umer_Farooq

    Thread Starter Member

    Mar 6, 2010
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    the problem tells in those thread that the output current has not accurately whose wanted output current very large difference


    the sgtwookie tell current is first please help me

    why voltage
    or
    why current

    thanks retched
     
  12. retched

    AAC Fanatic!

    Dec 5, 2009
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    Well if you want a variable voltage supply, you will use the current first voltage second. That way you have a stable current throughout the voltage range.

    If you want variable current, you want a stable voltage feeding the current regulator.
     
  13. Umer_Farooq

    Thread Starter Member

    Mar 6, 2010
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    i am design a variable 2-30V and 100mA-5A using lm338 supply
    both voltage and current variable
    than
     
  14. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    OK.. let's get some things straight..
    You want to design a variable PSU that can vary the voltage from 0 to 30V.
    And the features you want to have are that you need to control the current also from 0 to 5A.
    And also you like to have digital meters too.
    Am I right or what?
     
  15. Umer_Farooq

    Thread Starter Member

    Mar 6, 2010
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    you are right
    ok
    variable voltage design using lm338
    but current how to design 0-5A (this cct digitally design)
    idea using transistor or regulator ic
     
  16. retched

    AAC Fanatic!

    Dec 5, 2009
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    This is going to be very difficult. You will need fans and heat sinks to dissipate all the heat generated. The main transformer will have to be capable of the maximum you want to produce plus headroom for the regulators.

    You should consider a switch-mode design.

    goto and read:
    http://smps.com/Knowledge/free.shtml
     
    Umer_Farooq likes this.
  17. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    HeeeeeeeeeeHaaaaaaaaaw . OP is having a field day with a series regulator, and retched, u want him to make a SMPS...
    This is going to be hilarious :D.
    Can't wait to see the OP's response

    Umer....Do you know the relation between voltage and current.
    Tell me wht you know.
    Second Do you understand the terms constant voltage and constant current.
    Answer me these honestly and I will tell you what you can do.
     
    Umer_Farooq likes this.
  18. retched

    AAC Fanatic!

    Dec 5, 2009
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    I dont want him to make anything that he cant. I want him to have the information, so he knows what to ask.

    He should soon realize that buying a powersupply is way more cost effective than building one. But if he still wants to do it, smps.com is a good place to start.
     
    Umer_Farooq likes this.
  19. Umer_Farooq

    Thread Starter Member

    Mar 6, 2010
    104
    3
    oHM LAW V=IR


    whats mean OP
    constant voltage mean fix voltage or current




    Please help me for electronics knowledge i am a new student in electronics and i first project
    thanks
     
    Last edited: May 14, 2010
  20. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    U are telling me what the books say.
    I want to know what you understand. Tell me in ur words.
    If you really want our help.
     
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