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Class A amplifiers formulae help

  1. Nov 4, 2006 #1
    HI guys!

    well! i have got a question with me. Some forumlae i know and some i dont! please help me in solving it.

    There is a single stage class A amplifier which has

    Vcc =20V
    Vceq = 10V
    Icq = 600 mA
    RL = 16ohms

    We have to find:

    1) DC Input Power
    2) DC Power Loss in load resistor
    3) AC power developed across load resistor
    4) DC power delivered to the transistor
    5) DC power wasted in transistor
    6) OVerall efficiency

    okz, now i know how to find (1) and (6). What should i do for remaining. Following im wrtitng what i think about them. Please tell me if im wrong or correct. If im wrong then what is the correct formula:

    2) P = (Icq^2) RL
    3) P=0.5 Icq x Vceq
    4) dont know
    5) dont know

    Please tell me those formulae which i donot know and also make those confirmed which i have written above.

    i shall be thankful to u for this act of kindness.

    Good Bye!
  2. jcsd
  3. Nov 4, 2006 #2


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    Staff: Mentor

    Do you have a schematic of this amplifier? You can bias up class A amps in different ways to trade off THD versus quiescent power dissipation. Without more info, I don't think you can calculate several of the quantities you are asking for.
  4. Nov 4, 2006 #3
    Well! for the 1st question, i donot have a schematic. i have written that as it came to me. It is just written that it is a single stage class A amplifier. So please be straight forward.
  5. Nov 5, 2006 #4


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    Science Advisor
    Homework Helper

    I remember this as being thought of as the power consumed with no input signal supplied.
    This is not a clear concept due to the fact that "wasted" and "efficiency" vary with the input signal.
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