single stage amplifier

Discussion in 'Homework Help' started by nebula_fairy, Dec 5, 2004.

  1. nebula_fairy

    Thread Starter New Member

    Dec 5, 2004
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    I need some Help! :unsure:
    I need a basic description of a single stage amplifier. How does it work, what does it do, and also what the components do ( transistor! ). Any information, or directions towards info would be great!
    Ta very much!
    Neb
     
  2. Sandun Niroshana

    New Member

    Oct 6, 2008
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    I need a basic description of a single stage amplifier. How does it work, what does it do,about voltage gain and also what the components do ( transistor! ). Any information, or directions towards info would be great!
    Ta very much!
     
  3. S_lannan

    Active Member

    Jun 20, 2007
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  4. mahendradeshmukh

    New Member

    Aug 13, 2011
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  5. blah2222

    Well-Known Member

    May 3, 2010
    553
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    Well first off there are a number of different types of single-stage amplifiers that you have to be aware of. For the basics idea, consider the two main types of transistors: MOSFETS and BJTS. There are a bunch of other types of transistors, but they do relatively the same thing as these two.

    MOSFETs
    - n channel / p channel
    - enhancement mode / depletion mode
    - no base current
    - drain current = source current
    - current is proportional to square of voltage on the gate
    - cutoff, triode, and saturation operating modes based on gate voltage

    BJTs
    - npn / pnp
    - base current is present
    - current is proportional to exponential base-emitter voltage
    - forward-active, reverse-active, saturation, and cutoff operating modes based on base voltage in comparison to collector or emitter

    Once you become comfortable with working and understand the basics of how both of these transistors operate for DC conditions, then you can move on to AC analysis. You will need to cover:

    Determining DC Bias Q-Point
    - capacitors open circuit
    - inductors short circuit

    Small-Signal Models of MOSFETs and BJTs
    - using Q-Point values, determined small-signal linear parameters
    - DC sources become grounded
    - capacitors short circuit
    - inductors open circuit

    Once you figure all that stuff out, you can move on to your desired topic of amplifiers. You will cover the different configurations of single-stage amplifiers, the differences between MOSFET and BJT amplifiers, and little feedback loop tricks to give you more control.

    There are three main configurations for single-stage BJTs:
    - Common-Emitter (inverted gain)
    - Common-Collector (voltage follower, unity gain)
    - Common-Base (non-inverted gain)

    and

    The associated configurations for single-stage MOSFETs:
    - Common-Source (inverted gain)
    - Common-Drain (voltage follower, unity gain)
    - Common-Gate (non-inverted gain)

    I would really recommend getting a textbook and just learning through practice problems. If you are looking into buying a textbook I strong recommend either:

    Microelectronic Circuits - Sedra & Smith

    or

    Microelectronic Circuit Design - Jaeger & Blalock

    Though I think that the majority of lessons on this site are helpful, I really didn't find the section of amplifiers very clear, so I just bought a textbook.

    Good luck,
    JP
     
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