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I need a datasheet

Discussion in 'Datasheets, Manuals or Parts' started by riyantoro, Nov 23, 2004.

  1. riyantoro

    riyantoro New Member

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    Hi all
    I wanna make an amplifier type AB
    Anyone of you can help me please..
    What kind of transistor should I use?
    I have used BC 637 n BC 638 but i failed
    Help me please..

    Thanks
    :lol:
  2. Sebi

    Sebi New Member

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    Be more specific: need the output power (W), output (speaker) impedance (ohms) and the supply voltage....
  3. riyantoro

    riyantoro New Member

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    output speaker: 5W
    impedance 8 Ohm
    Vcc 12 Volt
    Imean the power supply voltage is 12 Volt..

    thanks for helping me..
    :p
  4. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    You can't get 5W into 8 ohms from 12V, unless you use a speaker coupling transformer, or a bridged amplifier (two amplifiers). Maximum power into 8 ohms off 12V is only about 2W for a normal single ended amplifier.
  5. hotwaterwizard

    hotwaterwizard New Member

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  6. riyantoro

    riyantoro New Member

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    Oh, that's too complex man..
    I'm still a beginner.. :p
    Well, i'm so sorry coz i wanna make an Amplifier type AB not type A like you mean..

    Then, i used a speaker with this specification:
    8 Ohm 1/4 Watt, not 5 Watt
    I still use 12 volt of Vcc
  7. TheOne

    TheOne New Member

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    Here is a simple design based around a common LF351 opamp that will drive a small loudspeaker. The transistors act as current boosters for the opamp. The transistors you mention would also work as any other small NPN, PNP pair

    The DC gain is 100 with the 3.9nF cap rolling off the gain at higher frequencies. Depending on what your input level will be you may need to have a potentiometer on the input to attenuate high input levels.

    Attached Files:

  8. Sebi

    Sebi New Member

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    Some simple? The LM386 from NSC.

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    • 386.gif
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  9. hotwaterwizard

    hotwaterwizard New Member

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    Here is one.

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