multistage common emitter amplifier

Discussion in 'Homework Help' started by Nabeel_mirza, Aug 26, 2010.

  1. Nabeel_mirza

    Thread Starter New Member

    Jan 16, 2010
    2
    0
    Hi

    A friend has asked me to design a multistage (Three stage) common emitter amplifier for him with a total gain of 900.

    The only info he has given me is as follows,

    Total gain = 900
    Re should be in the range of 1000 to 2000 ohms.....
    Coupling capacitors should be in the range of 10microfarad..
    BJT = NPN (2SC1815)

    n thats it...

    My question is "Is this info enough to design wht he asked for?". Coz i dnt think there is enough information.

    Looking forward to a fanourable reply...
    cheerzz

    Please let me knw wt u people think or is it just me who is being a complete novice..
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    What is the range of frequency response?
     
  3. Ghar

    Active Member

    Mar 8, 2010
    655
    72
    Specifying resistor and capacitor values is an odd way to start.
     
  4. Nabeel_mirza

    Thread Starter New Member

    Jan 16, 2010
    2
    0
    Exactly I told him the same thing bt he goes that this is only information he has n it could b designed..... as I knw the gain...... (Seriously no clue)

    So is it safe to say that there is nt much information to design the amplifier.

    Yes or No

    Thank you
     
  5. Ghar

    Active Member

    Mar 8, 2010
    655
    72
    You could do for that gain but it won't necessarily end up useful. That's really the only spec listed.

    You choose coupling capacitor values by specifying bandwidth... we can easily make the bandwidth poor and still use those values.
    Resistor values come from input resistance requirements, bias currents, etc. Since he already called it 'Re' it implies he has some kind of design in mind, since without a schematic a resistor value is useless...
     
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