12-31-2010 09:35 AM
I built the attached mixer with OP AMP 3T VIRTUAL. When I run the circuit it starts OK then the amplitude gets real big and I can not see it on the scope anymore. I built the same circuit with the OP AMP 5T VIRTUAL without connecting anything to the extra 2 leads and the circuit works. Is there a problem with the OP AMP 3T VIRTUAL device with AC signal inputs. I am using student version 11.0.
12-31-2010 10:30 AM
The 3pin op-amp model doesn't have a voltage limit and you can get really large Vout from it. Even if you didn't connect anything to supply voltage pins. Inside the 5-pin op-amp, there are additional circuitry and in this case it is helping the simulation to stay inside realistic range. I generally like to use the 5-pin model, it is usually more reliable.
03-14-2011 04:57 AM
i have tried using the 5t virtual opamp, but it does the same thing, the output disappers from the simulation window, yet im using (+) and (-) 12v supplies...what could be the problem now?