Emitter-Resistor Amplifier Design

Discussion in 'General Electronics Chat' started by Khalid Abur-Rahman, Dec 25, 2008.

  1. Khalid Abur-Rahman

    Thread Starter Active Member

    Dec 25, 2008
    the Amplifier is a capacitor coupled emitter-resistor amplifier..with a pnp transistor.

    it says it requires a voltage gain of -5, and an input resistance R(in)=1k, R(load)= 5k, Vcc=-12V, V(BE)= -.7 of course and hfe=200(which is represented by B, right?)

    so I have to choose the right values of R(C) and R(E)

    and from there I have to determine the current gain, maximum distorted output swing, and the resistor values of R1 and R2..

    does anyone have this stuff down well

    I've been trying, I picked the values of RE and RC before to give me an Rin of 1k but..it didn't give me a current gain of -1

    the answer key says the Ai or current gain is -1

    do I just have to basically keep guessing the right values and calculate?

    I'll be trying on my own...and hopefully I'll get some answers here..I know this is a hard one, or maybe easy for professional seasoned engineers.
  2. Audioguru

    New Member

    Dec 20, 2007
    The voltage gain is Rc in parallel with the 5k load/Re.
    The input impedance is beta x Re in parallel with R1 and in parallel with R2.

    Why do you talk about a current gain of -1? You want a voltage gain of -5.

    How simple. Didn't your teacher teach you?