Hello everyone, Hope you are doing great. I have designed a function generator for sine wave (V=5Vpp) by using LM324 OP-Amp. I am interested to design this generator for the frequency of 95.5Hz. I found this circuit online, after designing this circuit, i found there is no signal at any stage. I am afraid why is it? I designed this circuit in LTspice simulation tool. I need expert's help in this regard. The JPEG and .asc is attached for your review, please. I shall be grateful to you in this act of kindness.

 

hi Mike,
This is what I see, required the LTS timings adjust to run.
E

 

After you get the circuit running correctly, replace the last stage with a 2nd or 3rd order LP filter, to significantly reduce the distortion.
That is, If you do require lower distortion.

 

hi Mike,
This is what I see, required the LTS timings adjust to run.
E
View attachment 347329

Thank you so much for your kind reply. But i have another question that the output (sine wave) frequency is about 27Hz, but I want to enhance about 95.5Hz and output voltage's amplitude must be required about 5V (10Vpp). what values I need to choose for resistors and capacitors? I shall be grateful to you for this kindness, if you will suggest me appropriate values.

 

It will also start right up with the transient settings below:

 

It will also start right up with the transient settings below:

View attachment 347332

Thanks, sir, but how can I adjust the frequency and voltage amplitude as I mentioned in my previous post? Please suggest me.

 

Thanks, sir, but how can I adjust the frequency and voltage amplitude as I mentioned in my previous post? Please suggest me.

If you designed the circuit, as you said, how can you not know that?

 

If you designed the circuit, as you said, how can you not know that?

As I already mentioned in my first post that I find this circuit on the internet. So I just his his circuit.

 

how can I adjust the frequency and voltage amplitude

U1 generates the frequency. With a simulation you can easily change component values and see what effect they have.

 

U1 generates the frequency. With a simulation you can easily change component values and see what effect they have.

Sir, By changing the value of R1 only can I change or should change the value of C1 as well?

 

Within reason you can change either or both.

 

But i have another question that the output (sine wave) frequency is about 27Hz, but I want to enhance about 95.5Hz

As a first try, reduce all the capacitor values by a factor of 27/95.5 ≈ 0.283
To use standard cap values, change the RC values of each stage by that amount.