# Design of MultiStage Transistor Amplifier

#### MazKhan

Joined Mar 27, 2017
3
Hello I'm working on designing a multistage transistor amplifier with some specifications.

The specifications are as follows

1) Open circuit(no-load) voltage gain Avo = 50(+/- 10%)
2) Type of transistors is BJT
3) Maximum number of transistors is 3
4) Power Supply is +15V relative to ground
5) Output resistance can be a maximum of 15 kilohms
6) Input resistance has to be 200 or more kilohms
7) Quiescent Current drawn from the power supply can be at max 2mA
8) The Maximum no-load output signal swing can be no less than 8V peak-peak(-4V to 4V)

Can anyone give me tips on how to start designing the circuit?

#### JohnInTX

Joined Jun 26, 2012
4,358
Is this school homework?

#### MazKhan

Joined Mar 27, 2017
3
Is this school homework?
Im learning ahead for a course I am taking next year, and I just want to get used to the design of these circuits.

#### JohnInTX

Joined Jun 26, 2012
4,358
The reason we ask is to see if something should be put into Homework Help. This one seems to fit here OK.
Thanks for the clarification and welcome to AAC.

#### crutschow

Joined Mar 14, 2008
26,057
Can anyone give me tips on how to start designing the circuit?
Look at some tutorials on the design of BJT amplifiers.
Then come back to us with any questions you have about that.

#### MazKhan

Joined Mar 27, 2017
3
Look at some tutorials on the design of BJT amplifiers.
Then come back to us with any questions you have about that.
Alright, I'll get back to you after reading up on some of the tutorials. Thanks!

#### ian field

Joined Oct 27, 2012
6,539
Alright, I'll get back to you after reading up on some of the tutorials. Thanks!
If you're doing a bit of searching - you might run across a very handy 3 transistor amplifier from the very early days of transistors that runs on only 1.5V. It sometimes turns up when I'm looking for something else.

All 3 transistors are direct coupled - it has to be an odd number so that a resistor from output to input provides the nfb for stable DC conditions. If you want lots of gain; use two resistors in series for nfb and connect a capacitor from the join to GND to block the AC nfb.

It should work on 15V if you scale the collector resistors. The original 1.5V version could directly drive a 600 Ohm ear piece without breaking a sweat.

#### Bordodynov

Joined May 20, 2015
2,745
According to your technical requirements, I quickly developed an electronic circuit.
There are several feedbacks in it. I apologize for the delay. I was banned.
I hope that you will benefit by studying this scheme.