I have this electronics and circuit devices course and we were given a project on making our own two-stage BJT & FET amplifier that would produce a certain gain and frequency.

The requirements for the amplifier are:
2-stage amplifier (1 BJT, 1FET)
Av = 80dB
Bandwidth = 40kHz
Vcc = 3V - 5V
Input frequency: 20Hz - 20kHz @ 1mV

I don't really know where to start on the project because we were only taught how to compute values on a given amplifier circuit, not how to design one. A friend of mine gave me an example but i don't want to copy it. He has a drain feedback EMOSFET for the first stage and a voltage divider BJT for the second stage. I don't know why he chose those configurations and how he came up with those values. I'll have it attached below as an example.

I hope this community can help me through the project and thank you for reading

 

Start by looking at single stage G limitation for a FET or Bipolar amp.
What is limiting the G. The gain equation will tell you that. Thats a clue.

Then google compound transistor amplifier and look at some of the
possibilities, like darlington connection, or active load (fet used as load
in bipolar stage, clue)

Once you pick architecture then figure out how to bias the stages. Nominally
you want the collector/drain in single stage to sit at ~ 1/2 supply voltage.

Regards, Dana.

 

hi, did your friend or did you come up with a circuit of your own? haha i also have this project right now, but i have no idea how to :/ can i have what you did or what your friend did and can you explain to me the process? really desperate..