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Homework Help: Anlysis of transistor amplifiers

  1. Aug 18, 2007 #1
    i dont understand the difference between low ,high,midfrequency analysis of transistor amplifiers...what's midband analysis?
  2. jcsd
  3. Aug 20, 2007 #2
    Frequency analysis of transistor amplifier shows behavior of amplifier at different frequency. Like at low frequency effect of coupling & bypass capacitor becomes significant. So gain of amplifier changes with freq. In this region of frequency amplifier acts as High pass filter
    At high frequency internal capacitance of transistor affect the operation of amplifier.So here also gain of amplifier changes with freq. And In this region of frequency amplifier acts as low pass filter.
    in the midband(i.e. between low & high frequency) Gain of amp is almost constant. All capacitances are ignored in this region. Gain depends on value of passive element(resistors). So gain is independent of frequency:smile:
  4. Aug 20, 2007 #3
    thanks!!what are high pass and low pass filters?
  5. Aug 20, 2007 #4
    High pass filters are those circuits which allow higher frequency component of any i/p signal to pass & blocks lower frequency. And just opposite for Low pass filter. See the attachment. in low freq section gain is low and it increases with frequency. Thus allowing higher frequencies in that region to pass. & thus in low freq region it is acting as high pass filter. And same analysis for high frequency part where gain is decreasing with frequency. In attachment Bandwidth of amplifier is that portion which has Constant gain.:smile:

    Attached Files:

  6. Nov 25, 2007 #5
    thank u
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