current step down

Discussion in 'General Electronics Chat' started by pradeeba, Jun 24, 2009.

  1. pradeeba

    Thread Starter Active Member

    Feb 27, 2008
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    Hello,
    Is there any method to convert 30mA to 5mA?
     
  2. yusim

    Member

    Apr 27, 2009
    10
    0
    you could use 2 resisters in parallel as a current divider
     
  3. pradeeba

    Thread Starter Active Member

    Feb 27, 2008
    104
    0
    i dont want to divide. the total circuit current should be 5mA from 30mA
     
  4. studiot

    AAC Fanatic!

    Nov 9, 2007
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    513
    You need to explain further.
     
  5. pradeeba

    Thread Starter Active Member

    Feb 27, 2008
    104
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    I need a constant current of 5mA for my circuit operation. i have already derived constant current of about 25mA from PWM constant current generator IC for my wide range of input voltage. now i wanted to convert that 25mA to 5mA. How will i do that?
     
  6. studiot

    AAC Fanatic!

    Nov 9, 2007
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    513
    Since you haven't provided any real detail I cannot comment further, but you will have to create a suitable current sink for the other 20 mA, in parallel with your load.
     
  7. pradeeba

    Thread Starter Active Member

    Feb 27, 2008
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    0
    I need a constant current generator of 5mA for the input voltage range of 85 to 265 VDC. i got an IC HV9921 from which i can generate 20mA constant current. but i need 5mA output only. how to do that?
     
  8. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Do you know what a constant current is or have any idea of the implications of what you are asking?

    So far you have stated that you have constant current supply of 30mA, 25mA and now 20mA.

    Whatever your supply is it will adjust its output voltage to create that current in the load. Full stop . Period.

    Therefore whatever is left over from the 5mA you say you want has to go somewhere. You cannot restrict the supply to 5mA.

    You have been told this by myself and the other poster here, who seems to have given up.
     
  9. steinar96

    Active Member

    Apr 18, 2009
    239
    4
    pradeeba. You need to clarify further what your application for this is. It'll be easier for people to realize what you are trying to do and thus help you attain what you are looking for. Since without a context, simply stating that you need 30mA to 5mA and that you can't use a current divider doesnt get you far.
     
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