About ampilifing the current

Discussion in 'The Projects Forum' started by Transistor, May 17, 2007.

  1. Transistor

    Thread Starter New Member

    May 17, 2007
    3
    0
    :confused: Hi guys,:)

    I'm working in project called "Smart nursing", in this project we use microcontroller to control drawers to open in a certain times to remind the concerned people about the time of the medicine and the type.

    The microcontroller is sending signal to the drawers at a certain time to open and then another signal for the closing, but unfortunately the output signal which is from the microcontroller is V=5V and I=20 micro A. But the drawers need I = 200mA actually I tried many circuits to solve this problem like Darlington but I can't get the required current. Can any one help me please?.

    How can I amplify current from 20micro A up to 200mA?:)
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Use the 5 volt signal from the microprocessor to switch a logic-level FET. Select one that will handle 500 ma @ the desired voltage.

    Probably be better advice if we had a circuit to look at.
     
  3. mozikluv

    AAC Fanatic!

    Jan 22, 2004
    1,437
    1
    can you post the circuit you have made? maybe you have configured it in the wrong way. show us the schem and we can make appropiate suggestions.:)

    moz
     
  4. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Without a schematic of your circuit, our hands are tied.

    hgmjr
     
  5. Communications Student

    Member

    May 3, 2007
    10
    0
    I have asuggestion but i'm not sure, why don't he make a power amlifier circuit (class B) to amplify the current??
     
  6. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
    10
    You could use a op-amp wired as a voltage follower. You just have to connect the op-amp output to its "-" input, so negative feedback could be performed. For that you have to use an op-amp capable of delivering 200mA (I had in mind the LM324 but that won't do).
    You could search in: http://www.national.com/products/tree/table.do?treeId=14.

    But do you really need a current amplifier? Or you just want to process digital signals?
     
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