Current Limiter

Discussion in 'The Projects Forum' started by chrismightsmile, Sep 17, 2013.

  1. chrismightsmile

    Thread Starter New Member

    Sep 17, 2013
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    Hello, is this circuit correct? I am limiting a current from 6 A to 3 A. I need help. Thank you.

    Input: 12 V, 6 A
    Output: 12 V, 3 A [​IMG]
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    I am not sure why and what you want to achive here. I think this thread need more information. Where on net did you find that circuit you posted
     
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
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    U need to show the complete circuit.
    If those transistors are used to supply 3A, they will blow.
     
  4. chrismightsmile

    Thread Starter New Member

    Sep 17, 2013
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    This a current limiter circuit. I have a battery charger that supplies 6 Amps and i need it to go down 3A without changing its voltage. Do you guys have other suggestions or different circuit suggestions?
     
  5. #12

    Expert

    Nov 30, 2010
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    It doesn't matter where you found this. It is a concept drawing and it won't work at practical levels.
    First, use transistors that are bigger. That will make them smoke less.
    Second, understand that a 12 volt charger does not apply 12 volts. It applies more than 12 volts.
    Third, the limiting circuit will use up a little bit of the voltage. Probably not enough to matter in this case.

    Judging from the way you write words, I guess you are in a country where you could buy Radio Shack parts or Maplin parts. An NPN transistor that starts with "TIP" could be used for both of those 2N3904's.

    Make R1 = 39 ohms, at least 8 watts in size, and R2 will be about .22 ohms of at least 4 watts of size. Those are not Radio Shack parts. Better have some more discussion before you lay your money down.

    I have to go to the dentist now. Sorry, gotta go.
     
  6. wayneh

    Expert

    Sep 9, 2010
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    Is the problem is that your battery charger is too large for your battery? You need to prevent it from supplying a full 6A into a battery that can only tolerate 3A?
     
  7. chrismightsmile

    Thread Starter New Member

    Sep 17, 2013
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    yes, wayneh.
     
  8. t06afre

    AAC Fanatic!

    May 11, 2009
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    What kind of battery is this?
     
  9. chrismightsmile

    Thread Starter New Member

    Sep 17, 2013
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    lithium-ion
     
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