Connect with us

How to calculate the amplification of a common basis stage

Discussion in 'Electronic Basics' started by Geir Klemetsen, Nov 17, 2003.

Scroll to continue with content
  1. I know all the values, included the hfe for T1. And it's the voltage
    amplification I want to find.
    I'm loking for a formula to calculate it (not measure the input and
    output).


    Here is the schematic:
    (Best seen using fixed font Eg. Courier)

    +Ucc
    .-----------------o------------o
    | |
    | |
    .-. .-.
    | |R1 | |R3
    | | | |
    '-' '-'
    | | || V~out
    | o-----||-----o
    | | ||
    | | C2
    | |/
    .----o--------------|| T1
    | | |>
    | | |
    | | | || V~in
    | | o-----||-----o
    | | | ||
    | .-. .-. C3
    C1 --- | |R2 | |R4
    --- | | | |
    | '-' '-'
    | | |
    | | |
    '----o-----------------'
    created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de
     
  2. Baphomet

    Baphomet Guest

    Try this: http://www.tpub.com/content/neets/14179/css/14179_86.htm
     
  3. Baphomet

    Baphomet Guest

  4. John Larkin

    John Larkin Guest


    Assuming all the caps are big enough, Vin drives the emitter
    resistance of T1 (which should actually be Q1... 'T' means
    'transformer') , whose small-signal impedance is about re = 26/Ie, Ie
    being emitter DC current in milliamperes. So we now know the AC
    current into the emitter (factor in a bit of current lost into R4, if
    you're compulsive.) Now most of that (we lose a bit to the base from
    finite beta) shoots out the collector into R3 and becomes the AC
    voltage output.

    OK?

    John
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-