Hi GF
That's pretty good, close to vc=8.5v.
Added a 100mVpk, 1kHz sine wave input signal to show the performance.


Added: what do you make the Voltage gain, use the vc output plot.

E

 

I am just a bit late to the party.

A classic amplifier design consists of three stages.
(1) preamp stage
(2) driver stage
(3) output stage

The purpose of the preamp (1) is to provide high input impedance and moderate gain.
The function of the output stage(3) is to provide power, current gain, and low output impedance.
The middle driver stage provides additional voltage gain, low matching input and output impedance to match the preamp and output stage, along with additional low and high pass filter to meet the required specifications.

In addition, there should be negative DC feedback from the output to the driver in order to improve linearity and provide temperature stability. The driver would be DC coupled to the output stage.

The specs call for an input of 200mV and gain of 50. Hence the amplifier has to provide ±10V at the output. You need to calculate the current and power into the load.

 

Hi GF
That's pretty good, close to vc=8.5v.
Added a 100mVpk, 1kHz sine wave input signal to show the performance.


Added: what do you make the Voltage gain, use the vc output plot.

EView attachment 294809

Okay but the gain is to large now is it not ? I should only have a gain of 50 across all 3 stages.

 

Can someone explain why the Vc differs if I put my sources like this and not exactly like Eric's?

 

Think about how your sources are hooked up.

If you look at V2, the positive terminal is connected to your 0 V common (a.k.a., "ground") and the negative terminal is connected to your top rail. With the output voltage set to +15 V, that means that the top rail is 15 V LOWER than ground.

Now consider what it means to have a -15 V source (V3) connected with it's positive terminal connected to ground.

Are these the voltages you intended?

 

EDIT: I see that you must use a +15V and -15V supply.

 

If you search Google there are plenty of documents describing the process of designing an amplifier such as yours, including calculating the circuit elements.

There's no shortcut to understanding - you have to get your head around the principles involved.

 

Can someone explain why the Vc differs if I put my sources like this and not exactly like Eric's?
View attachment 294819

Because now you have 30V not 15V

 

If you search Google there are plenty of documents describing the process of designing an amplifier such as yours, including calculating the circuit elements.

There's no shortcut to understanding - you have to get your head around the principles involved.

I have googled and found nothing that is why I came to this forum. So if you can send me a link I will greatly appreciate it and try to solve it on my own.

 

I have connected my sources like I think they should be now.


Do you think I can continue to stage 2 now?

 

I have connected my sources like I think they should be now.
View attachment 294859

Do you think I can continue to stage 2 now?

They are exactly the same as they were.You still have 30V

 

Hi GF,
Calculate the new value for R1 to give the vc swing about close to 0v.

E

 

They are exactly the same as they were.You still have 30V

Before they were swapped. Vcc was -15 V and Vee was +15 V.

 

The specs call for an input of 200mV and gain of 50. Hence the amplifier has to provide ±10V at the output. You need to calculate the current and power into the load.

Hi C,
It is specified as 200mV peak to peak, for 50:1 gain, so +/-5V for Vout.
E
Clip:
The input signal shall be a 200 mV peak-to-peak sine wave

 

Hi GF,
Calculate the new value for R1 to give the vc swing about close to 0v.

E
View attachment 294861

When I do the calculations I get 76k but when I simulate it, it does not make sense.

 

hi GF,
Post your simulation file, I will compare results.
E

 

Here it is.

 

Hi GF,
How did you calculate R1 as 76.45K. ?
Try a value around 120K.
Post your calculations and simulation.
E

I assume you are using a BF=200.?

 

This is my calculations. Can you tell me what I am doing wrong?

With the 120k my simulation looks just like yours.

 

Hi GF,
I make the Q1, Ib approx 20uA, I will work through your calculations.

Would you try calculating R3 and R4 to set the gain for 10 at Vo1, on this test circuit.?

E