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Push-Pull Amlifier

PWKseeker_127eq

New Member
Good day, can anyone help me in this simulation of mine?
I need to simulate a push-pull amplifier.

In the first part, a dc operating condition:

I need to simulate the terminal voltages of transistors at dc supply VCC voltage such as:

VB1, VE1, VC1, VB2, VE2, and VC2.

The second part is running it in AC operation. Moreover, I need to be able to display 2 cycles of input signal.

And adjust the amplitude of the input sine wave voltage and rerun the transient simulation until the output voltage across the load resistor R8 becomes undistorted.

Also, I need to obtain the waveform of Vin, Vo(undistorted) .

Can anyone help me with this? I've been racking my brain for a several hours now and I can't get my desired output.

Advance Thanks for the feedback.
 

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crutschow

Well-Known Member
Most Helpful Member
A few observations:

If the circuit isn't working the look at all the circuit node signals to try to determine why.

What's the purpose of C1?
That would appear to be shorting the push-pull signal.

I see no statement defining the inductors as transformers.
All I see are a series of inductors.
Look up transformers in the help file.

Those inductances are way too low for an audio transformer.

Why do you have a DC offset for the GEN signal?
Transformers don't like DC, as it saturates their core.

What's the purpose of R1?

Use actual transistor models, not the generic SPICE model.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Yes, C1 shouldn't be there, and the resistor values seem rather bizarrely chosen as well - emitter resistors far too high, and bias resistors far too low.

The design and operation of this kind of antique circuit is entirely dependent on the transformers (it's back before they knew how to design transistor amplifiers), so it's crucial you get the correct transformer model.
 

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