I would like to build a simple circuit with a 555 timer, in monostable mode (monoflop). I looked at these two diagrams for this purpose.



Unfortunately, the simulation fails. Why is that?

PS: I am currently using PSpice for TI 2021.1, which means that I “only” have the parts and libraries from Texas Instruments and PSpice – so no time-controlled switch. So I use a pulse source that alternates between 0V and 5V.

I'd like to mention that I only do this type of electronics simulation as a hobby.

Many thanks for your corrections, I really appreciate them.

Edit: I found this site. Now I can use a time-controlled switch. This has settled this question, because the simulation was interrupted due to the pulse source.



cadence errors

  • 2
    \$\begingroup\$ Could you post the code instead of the image. It is easier for anyone here to copy/paste it in their own PSpice and play with it. \$\endgroup\$
    – 71GA
    Commented Sep 17, 2021 at 20:23
  • \$\begingroup\$ Could you tell me how I can get the code? \$\endgroup\$
    – Daniel
    Commented Sep 17, 2021 at 20:33
  • \$\begingroup\$ Code is the .asc file when you save. Copy it in with formatted code button. \$\endgroup\$ Commented Sep 17, 2021 at 22:01
  • \$\begingroup\$ I don't get an asc file. I let someone look for it. And saved the project again. Nothing, \$\endgroup\$
    – Daniel
    Commented Sep 17, 2021 at 22:17
  • \$\begingroup\$ Tell me, is it a disadvantage to have parentheses in the filename? Because I know that, for example, German umlauts are not allowed, otherwise the simulation will crash. \$\endgroup\$
    – Daniel
    Commented Sep 17, 2021 at 22:33

1 Answer 1


Your 470 ohms load is asking for a current of 5V/470 ohms= 10.6mA. But the datasheet of a Cmos 555 with a 5V supply has a 1mA output current, not 10 times more that you have.

Why is your schematic as large as my neighborhood with lots of space between its parts? I cropped it. Cmos 555 mono

  • \$\begingroup\$ I was just about to edit my question here, then I saw your answer. I changed the RV to 5kΩ. What I want to say: To misuse this pulse source as a "switch" – because I have nothing else – is simply nonsensical. Therefore the simulation stops. What can I do to generate a voltage change during the simulation (12 seconds) so that you can see an effect? \$\endgroup\$
    – Daniel
    Commented Sep 17, 2021 at 23:35

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