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simulation

Sandor Nyerges
Prodigy 120 points

Other Parts Discussed in Thread: TINA-TI

 

I have this circuit:

and I would like to simulate it to make sure that it work as I think it should.

Some number of milliseconds into the simulation I want to flip the switch on and then at some later milliseconds turn it off, and I would like to see how the voltage over the load resistor develops.

Which kind of simulation should I choose, how do I prepare for it, how do I run it and capture the output?

Also, when I dropped the transistors in, they came labeled with a question mark. What does that mean?

Thanks, Sándor

 

 

  • 0
    TI__Intellectual 2290 points

    Hello Sandor,

           Could you please repost the schematic you are trying to simulate in another format for some reason I'am not able so see it, maybe a .jpg will do the trick.

    Regarding the question mark, I believe bipolar transistor might have an exclamation point before its type for example !NPN or !PNP, this means that this particular device is a generic device whose parameters can be adjusted by the user by double clicking on it. I hope this answers one of your questions. Try to upload the schematic that you are trying to simulate and we'll be glad to help you as best we can.

    Thanks and best regards,

    Marcos.

  • 0 in reply to Marcos López - Online design tools
    Prodigy 120 points

    Marcos

    Thanks for replying so fast.

    Yesterday, as I was entering my question, I could see the schematic embedded in the text right where I pasted it, but when I clicked on the "Review" button and I did not see it. I assumed that by the time it got the forum it would somehow make it. I see now that it didn't.

    Well, it was a .JPG to begin with, and just now I tried other formats: bitmap, .PNG, .TIFF, .GIF. None of them were visible in the review window, which means you can't get them either.

    Maybe my editing method is not right. Windows XP, TINA-TI displaying my schematic, I hit "Print Screen", then I start Paint and I ^V to paste it in, trim the whole screen down to just the schematic, save it as one of the above mentioned formats, and use ^C and ^V to copy and paste it in this editing window. It shows up fine, but in "Review" and evidently in the real "Post" it is lost.

    How do I get it in? My browser is Mozilla Firefox 5.0

    Regards, Sándor

     

     

  • 0 in reply to Sandor Nyerges
    TI__Intellectual 2290 points

    Sandor,

            Let's try one thing, instead of directly copying and pasting into the editing window, try uploading the file into your post. You mentioned you used the "preview" tab from the menu, to the left there should be an "Options" tab, click that one and you will be redirected to a window where you can upload your file. Try what I mentioned and let's see if we get this running.

    Regards,

    -Marcos

  • 0 in reply to Sandor Nyerges
    TI__Intellectual 2290 points

    Sandor,

            Disregard my last post, there is an insert image button, see image below. I apologize for the confusion.

    Regards,

    Marcos

  • 0 in reply to Marcos López - Online design tools
    Prodigy 120 points

    Aha! Here it is:

    now we can get on with it. And, you are right, the transistors don't have question marks, those are exclamation marks.

    Sándor

  • 0 in reply to Sandor Nyerges
    TI__Intellectual 2290 points

    Hey Sándor,

           I conected the circuit in Tina and ran a transient simulation. From inspection the cicuit looks like a latch thus the voltage across Rload should go High when voltage is applied to the base of T1. I added an extra switch to ground (SW2 in the schematic) to restart the latch. Also instead of using a time controlled switch, I used a voltage controlled switch with a piece-wise linear voltage source as trigger, that gave me the flexibility of turning on and off the switches at any specific time. I have attached the schematic, take a look and let me know if you have more questions.

    Regards,

    -Marcos

    Latch.TSC
  • 0 in reply to Marcos López - Online design tools
    Prodigy 120 points

    Marcos

    Thank you for that. Are those voltage controlled switches tri-stated? In other words does the software simulate a floating base resistor R3 when the switches are not activated? How did you change the colors of the waveforms? Is there a way to tie the colors of waveforms to the colors of voltage pins?

    Sándor

  • 0 in reply to Sandor Nyerges
    TI__Intellectual 2290 points

    Sandor,

            The switches have two different resistance values, when the switch is ON I set the resistance to be 1 ohm and 100e6 Ohms when the switch is OFF, thus in the dead time when both switches are off you should see a voltage divider from VDD to Gnd across the two OFF resistances of the switches which feeds into resistor R3. If you use only one switch to VDD you will see a similar effect because since no current is going to flow from VDD to the base of T1 no voltage is lost across R3 thus you will have a value close to VDD in one of the legs of R3. I will assume that once the circuit latches the voltage at the base of T1 will be set by the positive feedback loop thus the only way of resetting the latch is to pull R3 to GND. Regarding the colors of voltage pins, I don't know a way of assigning the color of a waveform from directly from the voltage pin, the waveform will follow the name that you assigned in the schematic but you don't have control over the color, however you can do all sorts of post processing in the diagram window, you can split the curves into different displays, change the colors, etc. Just go under the View pull down menu on the diagram window or double click on any of the plots and see the different options you have. Let me know if you have further questions.

    Regards,

    -Marcos.