PNP Transistor is not Active

SimulIDE_1.0.1-R1374_Win32

On the attached schematic, the collector voltage of BJT-4 (PNP) is constant (DC) and changes by varying the value of the 15K resistor at its base.

Note:
The WaveGen-1297 toggles between 5V and -5V instead of 0V and -5V (Semi Amplitude 2.5V, Middle Voltage -2.5V).

WaveGen problems solved at trunk Revs 1397 1398.

arcachofo wrote:WaveGen problems solved at trunk  Revs 1397 1398.

You wrote problems though I thought there was one WaveGen problem only.
Perhaps you meant you also fixed the PNP problem.

You wrote problems though I thought there was one WaveGen problem only.
Perhaps you meant you also fixed the PNP problem.

There was an extra problem in WaveGen that seems to cause the problems in transistors.

arcachofo wrote:

You wrote problems though I thought there was one WaveGen problem only.
Perhaps you meant you also fixed the PNP problem.

There was an extra problem in WaveGen that seems to cause the problems in transistors.

I see.
But is it for BJT only or MOSFET too?
If no problem in MOSFETs, I can replace BJTs with MOSFETs, at least temporarily, after setting their parameters properly.

But is it for BJT only or MOSFET too?
If no problem in MOSFETs, I can replace BJTs with MOSFETs, at least temporarily, after setting their parameters properly.

I'm not sure, but it will probably work with Mosfets.
Indeed I still have to investigate the issue with BJTs.

To produce a crash by ‘Undo’, I closed and re-opened SimulIDE several times while simulating test_6.sim1 (uploaded earlier). I was surprised that sometimes, not always, the PNP works as expected! It does in this same circuit and without modifying it in any way!

About the crash produced by ‘Undo’, I am afraid it happens somehow at random and once a while. I mean, every time I repeated exactly what I did before every crash, I got no crash!

I closed and re-opened SimulIDE several times while simulating test_6.sim1 (uploaded earlier). I was surprised that sometimes, not always, the PNP works as expected! It does in this same circuit and without modifying it in any way!

Yes it is random, that is why I thought it was solved with the WaveGen fix.
But the problem with BJTs is still there.

I finally found the cause of the "randomness" and fixed it, so at least it behaves consistently for a certain circuit and now I can debug it properly.
The problem with BJTs is really weird and it is probably not in the BJT model.

About the crash produced by ‘Undo’, I am afraid it happens somehow at random and once a while. I mean, every time I repeated exactly what I did before every crash, I got no crash!

The problem with Windows is that is closes a program if it becomes "irresponsive".
So it is difficult to know if it is an actual crash or it is just taking "too long" to perform a task.

I suspect that it can be related with an interaction with "Auto-Backup".

arcachofo wrote:
The problem with Windows is that is closes a program if it becomes "irresponsive".
So it is difficult to know if it is an actual crash or it is just taking "too long" to perform a task.

I suspect that it can be related with an interaction with "Auto-Backup".

I will consider what you pointed out here when future crashes will happen.

Finally I found the problem with BJTs (it is not really in the BJT model).
But is a mathematical problem and I'm not good at mathematics.
If someone with good knowledge in algebra could help would be great.

The problem is about solving a system of linear equations in matrix form by LU factorization.
To reduce round-off errors, rows are swapped to have the largest pivot in the diagonal.
But in some cases this is generating big errors and I don't know why.
My brain just refuses to follow the operations...

By now I just disabled the pivot conditioning and it seems to work correctly, but this could cause errors in other cases.
So if someone can give a hand, we could try to find a better solution.
Or maybe I will try in next days when my brain stops to hurt.

Did you try this circuit in 1.0.1-R1386?

arcachofo wrote:Did you try this circuit in 1.0.0-R1386?

Not yet, I was going to use it.

By the way, the previous failure in simulating the use of BJTs to drive a triac (as the KT207-600V I have), gave me a chance to study how it could be driven directly by the MCU pin (ATmega8L or ATmega8A), with a good margin below its absolute ratings. And it worked.

But I will re-test the previous circuit with BJTs by running the new version, SimulIDE_1.0.1-R1386_Win32.

I tested all previous circuits having BJTs. They all worked as expected. Thanks.

I tested all previous circuits having BJTs. They all worked as expected. Thanks.

Thank you very much.
I was worried about last changes.