Hello everyone,
I need to build an amplifier with a voltage gain of 1000, and the fact is that i need to use 2 NPN 2N2222, and they must be in one stage.
I tried some design around a Darlington pair, and even invented on myself. With the simulation, i effectively can find an voltage gain of 1000, but i can't find it by calculations...

Here is the build i made.
If you have ideas or other builds to propose, i would taking it !
Ve is 1uV !! My mistake.. I need to express Vs / Ve ( Vs is taken at the CQ2 )

 

Bonjour. Welcome to AAC!
Is this homework?

 

Bonjour. Welcome to AAC!
Is this homework?

It's mixed between Homework and actual work, i'm working at STmicroelectronics while i'm an engineering student. Its a work that i will show at my school and at my work team

 

I would split the gain into two stages, for example, 50 x 20.
Do you know how to design a single stage common emitter BJT amplifier?

 

I would split the gain into two stages, for example, 50 x 20.
Do you know how to design a single stage common emitter BJT amplifier?

Yeah, that would be the best thing to do. The fact is that the 2 NPNs must be in one stage (like a darlington pair or the circuit on the image). That's why i'm struggling with calculations

 

What is shown is a 2-stage amplifier, not a Darlington amplifier.

 

Yeah, that would be the best thing to do. The fact is that the 2 NPNs must be in one stage (like a darlington pair or the circuit on the image). That's why i'm struggling with calculations

Excuse me for living, but the schematic in your diagram shows a 2 stage amplifier. Is it possible you have a basic misunderstanding of what a stage is?

 

Excuse me for living, but the schematic in your diagram shows a 2 stage amplifier. Is it possible you have a basic misunderstanding of what a stage is?

It's not considerated as 2 stages, because the two transistors are not statically isolated

 

What is shown is a 2-stage amplifier, not a Darlington amplifier.

Yes, i tried with a darlington pair, but couldn't go superior than 30dB of gain. Also the one on the picture is not considerated as a 2 stage amplifier, because the two transistors are not statically isolated

 

There are many sites that discuss the Darlington amplifier.

https://www.electronics-tutorials.ws/transistor/darlington-transistor.html

 

Also the one on the picture is not considerated as a 2 stage amplifier, because the two transistors are not statically isolated

You are going against convention. What authority says they have to be 'statically isolated' to be regarded as separate stages?

 

You are going against convention. What authority says they have to be 'statically isolated' to be regarded as separate stages?

My teacher... I only need to build an amplifier with 2 NPN, wich are not isolated statically

 

There are many sites that discuss the Darlington amplifier.

https://www.electronics-tutorials.ws/transistor/darlington-transistor.html

The darlington ampllifier is mostly used as an Current amplifier, this circuit cant handle voltage gain of 1000. My question is just how should i express Vs/Ve of the circuit on the picture

 

Hmmm…. Perhaps something is lost in the translation, but what do you mean by statically isolated?
Never have heard the term.

 

Hmmm…. Perhaps something is lost in the translation, but what do you mean by statically isolated?
Never have heard the term.

I mean... Just separated by a condensator

 

That is called DC coupling between the stages, it does not make it a single stage.

 

What is the required frequency response of the amp?

Note: The curved lines on your schematic are cute, but you need to put dots on all the junctions that are connected.

 

That is called DC coupling between the stages, it does not make it a single stage.

Okey, my bad... But it doesnt answer my question at all... How can i express Vs/Ve of this circuit ? Or, if it's not possible, what is the best solution, to have a voltage gain of 1000, without " DC coupling between the stages "... Thx !

 

What is the required frequency response of the amp?

Note: The curved lines on your schematic are cute, but you need to put dots on all the junctions that are connected.

I just need to have 60 dB at 1kHz ( sorry for the dots, everywere the lines are crossing, there is a dot )

 

how should i express Vs/Ve

Where is Ve?
What is the purpose of RB22?