NEED HELP IN designing a class A amplifier

Discussion in 'Homework Help' started by kadomori, Mar 20, 2011.

  1. kadomori

    Thread Starter New Member

    Jan 29, 2011
    hi professors.

    please help me in designing a class A amplifier. i want a power output of 10 watts for 8ohms load.
  2. bertus


    Apr 5, 2008
  3. kadomori

    Thread Starter New Member

    Jan 29, 2011
    oh. yes . thanks for the link.

    look at this.. 09.pps

    look at page 9-5 of the powerpoint file . something like this is what i want to obtain .. the cascaded amp. was put together with power amp. do you know why it's need to put them together?
  4. mjhilger


    Feb 28, 2011
    Q1 is used as a voltage amplifier. It's output impedance in that design is 1K. While the voltage was amplified, it will not drive much of a load. The power stage are set in an emitter follower configuration. It amplifies current but no voltage. In this particular setup, the base current necessary to drive the final output Q3, is more than the output of Q1 can provide. So Q2 is added in conjunction to Q3 in a Darlington setup to amplify the current many times more, lookup Darlington for more info. The beta of the Q3 transistor is increased
    [​IMG]C3 is a DC blocking cap allowing the coupling of the initial voltage amp to the power amp back section.