Cascade Amplifier

Discussion in 'Homework Help' started by JeromeDarshana, Sep 18, 2010.

  1. JeromeDarshana

    JeromeDarshana Thread Starter New Member

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    hi i need to make an amplifier which has

    gain of 15

    output impedence of 30 Ohm

    input Impedence of 30 kOhm

    this must be a cascade amplifier.

    can some one explain how to do the calculations ??

    i need all the formulas and the was how they determine :)
     
    #1
  2. Ghar

    Ghar Active Member

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    Don't make duplicate threads.

    Formulas go with schematics, you have no schematics.
     
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  3. retched

    retched AAC Fanatic!

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    #3
  4. Audioguru

    Audioguru New Member

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    He doesn't want a cascode amplifier. He wants to cascade amplifiers or he doesn't know how so spell correctly.
     
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  5. retched

    retched AAC Fanatic!

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    Jeez a wheez.

    Please forgive me. I read it incorrectly. (Or hopefully im psychic and he spelled it wrong ;) )
     
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  6. JeromeDarshana

    JeromeDarshana Thread Starter New Member

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    i need cascade amplifier not cascode :p
     
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  7. Audioguru

    Audioguru New Member

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    Did you look at the cascade amplifiers in Google?
    They are simply one amplifier that is amplified by another amplifier.

    The gain is only 15 so it should be easy. The first stage can be a common-emitter transistor.
    The output impedance is very low so it should have an emitter-follower or a pair of complementary (NPN and PNP) emitter-followers as the second stage.
    The input impedance is fairly high at 30k so the first transistor should have a fairly low current and an emitter resistor to increase the input impedance and reduce the gain.
     
    #7
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