开云体育

Hello Neil If I understand correctly, you want something like this: .meas t1 param 6.3m .meas t2 param 7.3m .meas a avg v(x) from t1 to t2 .meas b rms i(v1) from t1 to t2 . . . Alternatively, you can

BB, thanks for the tip on capturing and viewing subcircuit parameters! When I add those 0V sources, I’ll do a side by side comparison with a version that uses the model currents. Appreciate the

Hi Jim, The approach I have taken is to gather the 2 port s parameters for a box full of say 3904. Then use the s data with a waveform arithmetic statement in LTSpice to get ft. As ft is an

If you want to view the .subcircuit values in the waveform viewer, you can (even though you cannot seem to use them in the circuit as you wanted) go to Tools-->Control Panel-->Save Defaults and click

Bad 'black market' parts even fall into the mainstream distribution channels.? You need to know your sources very well. Andy

This is as good an explanation as I could have hoped for. ?I really appreciate your insight on this... it makes sense. ?Perhaps it’s just a missing feature in LTspice, or perhaps it’s by design

You mean like those “grab bags” that can be gotten for a pittance at a swap meet? Got a bunch of those and now they are mixed in with good stock :=(( Wonder where those that are marked with the

And then there is the question of where your distributor got THEIR parts.? These days, some are rejects that fall off the datasheet.? Watch out for that. Andy

I think Helmut's recommendation in this case would be to use the PSpice docs.? Helmut used PSPCREF.pdf which can be downloaded from many places on the net.? Then turn to the chapter on BJTs and read

Neil wrote, "I am using a .meas file to run after the simulation completes." I just want to clarify one thing, which is probably obvious.? You run this .MEAS script from the waveform viewer, right??

Sorry, I should have thought the question through, more carefully. Of course, beta and Ft depend on voltage, current, and temperature, I guess that what I’d like to figure out is where, in the

I am using a .meas file to run after the simulation completes. As this has now grown considerably being able to use text substitution would help enormously but I can't figure out the syntax. For

It's not really that the FET current signals are being 'created' when using a non-subcircuit FET.? All device currents are already there.? Every element has a current through it, or into its pins

Ix() currents cannot be used in arguments for B sources, you only seem to be able to use the current of a primitive. I don't know why either. -- Regards, Tony

The two parameters (beta and Ft) you've chosen have no fixed value; they both vary with Ic, Vce and temperature as well as sample to sample. If you mean BF and not beta, then that's a different

Andy, thanks for having a look! Maybe that’s it. ?The question of how these variables are created in the netlist also crossed my mind, but was unable to find anything on it. So, with models found

Greetings folks - I wonder if there is a way to estimate any of the first order bjt parameters, such has dc beta or Ft for a model? Yes, a test bench could be created but I was wondering if one could

I am not entirely positive, but I think the explanation is something like this: When the simulation runs, LTspice has the expanded netlist.? There is no Ix(M1:D) or Ix(M1:G) in the netlist, so you

Hmm, Ix(M1:D) should work, but maybe not here?? (Don't know why.) You could add a 0V voltage source in series with the Drain pin and use that in the formula. Andy

What is Ix(M1:D) supposed to be? Obviously, that syntax isn't right. Andy