need help to simulate oscillator in orcad

[aries]

Please can any one help me in simulating an oscillator in orcad. I have designed an oscillator using opamp but its not working. i have als applied the initial conditions also but still its not working.

 

[babar_ali]

Hi, Can you tell me which Orcad version are you using. The best way to solve these problems are to upload your files and the calculation made.

 

[crutschow]

Sometimes to get a oscillator started in simulation you need to add a little perturbation to simulate the noise in a real circuit. One way to do that is to add a short single pulse of current to the oscillator loop using a current source. (Don't use a voltage source since that will short the loop to ground.)

 

[Winterstone]

Please can any one help me in simulating an oscillator in orcad. I have designed an oscillator using opamp but its not working. i have als applied the initial conditions also but still its not working.

If it is "not working" - perhaps it is not really an oscillator, which means: Does the circuit meet the oscillation condition (Barkhausen)? Show us your circuit diagram and you will get a definite answer.
Regarding Chrutschow`s remark: It is correct - however, of course you can also use a short voltage pulse, if it is applied to any node that is already grounded.

 

[kubeek]

... you can also use a short voltage pulse, if it is applied to any node that is already grounded.

How do you apply a voltage pulse to a grounded node?

 

[Winterstone]

How do you apply a voltage pulse to a grounded node?

Is this a serious question?
Of course, by lifting that node and to connect a one-sided grounded source to it.

 

[kubeek]

Absolutely serisous, I understood it as applying voltage to a node that IS grounded. I think saying "... that was initially grounded" would be a lot clearer.

 

[Winterstone]

Absolutely serisous, I understood it as applying voltage to a node that IS grounded. ....

Was this really your understanding? I suppose you were able to read between the lines. I am not silly enough to connect a voltage source between ground and ground. But it seems that my knowledge of the english language should be improved.
Nevertheless - thanks for replying.

 

[ronv]

Attach the circuit. It will help