Post by thread:[EE:] PSPICE

Hi Guys I am learning how to use ORCAD PSPICE and I have done an inverting amp circuit with an opamp as normal. Apart from the usual resistors for gain I fitted a resistor from non inverting input to ground. I am getting an error on that node it keeps on telling me that there are less than two connections on that node! the resistor is connected on one side to ground and the other to the opamp so there are two connections... is it the ground connection ? Can someone help. thanks best regards Luis -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email spam_OUTlistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

Luis Moreira wrote: > I am learning how to use ORCAD PSPICE and I have done an inverting amp > circuit with an opamp as normal. Apart from the usual > resistors for gain I fitted a resistor from non inverting input to ground. I > am getting an error on that node it keeps on telling me that there are less > than two connections on that node! the resistor is connected on one side to > ground and the other to the opamp so there are two connections... is it the > ground connection ? Can someone help. Luis, Are you doing this with the Schematic editor, or is it a hand-generated netlist? Can you post it here? I'm curious what symbol or node you're calling "ground", for one thing. Jim > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

Hi Jim sorry about the delay on answering, but this is my email at work and I just went home on Saturday before your answer. I am using the schematic editor and I used the GND/CAPSYM symbol from the place ground menu (orcad 10.0) best regards Luis {Original Message removed}

Luis Moreira wrote: > I am using the schematic editor and I used the GND/CAPSYM symbol from the > place ground menu (orcad 10.0) Luis, I'm not 100% sure if that's the "correct" ground symbol for your Analog circuit... If I recall, the one you want is "AGND"; but I haven't used the Orcad package since version 9.0, so I'm not sure if something might have changed. But, come to think of it, you're not specifically saying that the ground point of the resistor is causing the complaint, right? Is it the op-amp input node that it's complaining about? If you could post the netlist from the schematic it might help. Jim > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Hi Jim thanks very much for your help but I just manage to make it work. I think this is some kind of bug... I spoke with someone else that uses this package and they had exactly the same problem, because I was using a generic opamp it does not need the offset compensation resistor on the non-inverting input to ground. It actually will not allow it. what I have done was to fit a second resistor in parallel with the other one and that's it. best regards Luis {Original Message removed}