Power Push-Pull Amp ( class AB )

[ENG.Kholoud]

Hi :shy:

I'm a new member here

for a long time I'm looking for a help in my project Power Push-Pull Amp ( class AB )

Can anyone help me with circuit diagram in Multisim for class AB or anything

 

[Jony130]

What exactly do you have a problem with?

 

[ENG.Kholoud]

I had a circuit it is work in Multisim, but when I build it a real one

It doesn't work !

 

[Jony130]

Show us full circuit diagram.

 

[Crazymechanic]

Hi , well from my experience I can say that Multisim isn't always so accurate on some circuits when testing them.As real life is close to the book but not by the book always.
i just built some multivibrators and in real life with the exact same parts and circuit they behave different than in simulation.
You should show us the circuit to tell you more about it but basically any amplifier should be built stage by stage , you build one stage at a time then check it test it and if it works then build the next one.
I built an AB class push-pull amp too and firstly I had some problems but then it was just error correction and some faulty parts and everything went on.

Also it would be great for you to tell us not only the circuit but from where you got it.Some sources on the internet are not reliable at all and some are there because they put scams on the internet just for fun so that someone who isn't experienced enough would have problems with building one.

 

[ENG.Kholoud]

Hi , actually it is a circuit for ( Electronic Devices (Conventional current version) ) book P368

I hope it is clear

First I used as it said in the book (in Multisim) :

3 Resistors + 3 Diodes + (2 transistor: 2N3904 + 1 transistor: 2N3906 + 2 transistor: BD135 )

but the wave doesn't amplified, after that I add 1 capacitor in the input and another three Resistors ( R Load in the output ) it amplified.

in real, I do the same, the output amplified. The problem is I want to see the top half wave and the bottom half wave. I tried to separate the Q1 and Q2 from the circuit and test it, but it doesn't work ! and the same for Q3 and Q4 !

 

[Jony130]

You should never built this Push-Pull Amp in the first place.
First you should add 1 ohm emitter resistor to Push-Pull stage. And use R1 resistor to set 0V at output without input signal .

 

[Enthalpy]

I can't imagine people assemble an audio amp from discrete transistors in the 21st century. There are integrated circuits for that.

We did use discrete transistors when I was a teenager, and I have grey hair now.