Zero crossing detector simulation

[ahmelsayed]

hello every one,
I'm trying to simulate a zero-crossing detector circuit on Multisim but it gives me a strange results !
I attached both the circuit and the result.
can anyone help me with that ?

Thanks,
Ahmed Elsayed

[lenny]

hello Ahmed Elsayed,

I think the input voltage of the  OP may not exceed approx. 30 V. The amplitude of the sine input seemes to be more than 200 V.

With less or equal  25 V it will function very well.

I hope this helps.......

[ahmelsayed]

Hello Ienny

Thanks for replying, i do like you did in your attached image but it still give me strange results.

i beleive it's an error in the ciruit altough it is a simple one -comparator in any test book- and it is not a multisim bug !

here is the second exp. results.

Thanks for help.

[lenny]

Hello Ahmed,

I think your input voltage is still to high. I cannot reproduce your results.

Which model are you using for the LM324AD? There are six different models available in the main database.

I used the default model Motorola/LM224_6.

The model LM324_2 has no limitations with respect to the supply voltage of the OpAmp.

Hope this helps....

lenny

[ahmelsayed]

Hello Ienny,

thanks for trying to help. 'm using the same model you use (Motorola/LM224_6) !

if you could attach your multisim file, i may figure it out.

[lenny]

Hello Ahmed,

Itried to answer to your e-mail and to attache the multisim file but i got an error from the NI server.

I don't know how to attache the file to my response at the discussion forum. There are only image or video files allowed.

Perhaps you can send me a private message with your email address and I will send you the multisim file immediatly.

[suribright]

Hi, what chip will you use if we have input frequency about 20Mhz of above zero crossing detector circuit? I have this challenging this moment. Anyone know this please help. Thanks