# Emitter-Resistor Amplifier Design

#### Khalid Abur-Rahman

Joined Dec 25, 2008
34
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.

#### Audioguru

Joined Dec 20, 2007
11,251
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?