Hi Frends
I am new in electronik and also Orcad capture, sso I am trying to understand a circuit building square wave . I simulated the circuit in Pspice. Unfortunately, my simulation does not work.
I replaced the following coponnents in P-spice
HEF4049 replaced by 7404
MMSD4448 replaced by1na4151
my simulation always gives a constant voltage at the output and no square signal, what is wrong?
i can also upload my simulation files if need??
thanks a lot

 

Welcome to AAC!
Oscillator circuits which are perfectly symmetrical can confuse Spice. Try introducing either slight asmmetry or a low-amplitude noise source to kick-start things.