Your Favorite Constant Current Source Circuit

Discussion in 'The Projects Forum' started by MCU88, Mar 17, 2015.

  1. MCU88

    Thread Starter Member

    Mar 12, 2015
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    Hello...

    What is your favorite constant current source circuit?

    I recently made this one:

    [​IMG]

    [​IMG]
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Depends on what current range you need, Lm338,lm317, opamp, Jfet, transistor diode,...
     
  3. MCU88

    Thread Starter Member

    Mar 12, 2015
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    Hello...

    Text is cheap. Please post some schematics of your schemas for constant current.
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Is google not working today???
     
  5. MCU88

    Thread Starter Member

    Mar 12, 2015
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    This is not about google this is about here. Go and take some painkillers for your headache.
     
  6. MCU88

    Thread Starter Member

    Mar 12, 2015
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    Hello...

    Provide circuits for say:

    a. Precision 1uA to 5mA usage
    b. 5mA to 500mA
    c. 500mA to 50A

    Thanx!
     
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
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  8. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    You go first.
     
  9. WBahn

    Moderator

    Mar 31, 2012
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    What are the specs? What do you consider "precision"?
     
  10. WBahn

    Moderator

    Mar 31, 2012
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    The schematic in Post #1 doesn't match the circuit shown in a few respects.
     
    wayneh likes this.
  11. OBW0549

    Well-Known Member

    Mar 2, 2015
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  12. crutschow

    Expert

    Mar 14, 2008
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    The circuit shown in post #1 is a reasonably good constant current circuit but I won't call it "precision".
    One fault is that the current is temperature dependent as it is determined by the Vbe of Q1 and that changes about 2mV/°C.
     
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