I made a project of monostable flip flop using 555 timer in pspice. Now I need help with simulation. Problem is that I'm just statring my adventure with pspice and I have no clue what I'm doing wrong. I guess there is something wrong with Trigger configuration (Vtr - rectangular signal) and I don't know how to configure Setup Analysis properly. I'm trying to achieve output waveform and voltage across the capacitor C.

555_mono_sh direct link to .sh file.


1 Answer 1


I don't know which version of PSpice are you using. But after adding TR and TF a small value, it works. Usually a 1 picosecond rise/fall time is extremely small with regard to the simulation time, so it closely approximates the ideal step function. Set them to 0 may cause convergence problems in some transient analysis simulations.

  • \$\begingroup\$ Like I wrote, I new in pspice and I don't know how to configure it :). Can you help me with that? I know that I should setup values it and change Setup Analysis. \$\endgroup\$ Nov 30, 2014 at 14:23
  • \$\begingroup\$ Set the TR and TR parameters of the VPULSE source (Vtr) to a small value such as 1ps, that should be OK. \$\endgroup\$
    – diverger
    Dec 1, 2014 at 1:35
  • \$\begingroup\$ If you want to see voltage acroos C the arrow must be placed ABOVE the capacitor (otherwise, you measure always 0 volts). \$\endgroup\$
    – LvW
    May 11, 2015 at 13:14

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