Problem with Proteus ... Square Wave Generator Example

[MAAASD]

Problem with Proteus ... Triangular Wave Generator Example

Hello all,
I've designed a square wave generator on proteus and i want to check its output on the
virtual graphic mode but it seems i've a problem with the design itself
I got this error "Singular Matrix : check node ....."
here is the simulation file
View attachment Triangular_wave1.zip
Your help is much appreciated

- - - Updated - - -

It's a Triangular wave not square wave sorry

 

[MAAASD]

sorry it need to register to download your file.
here is a circuit of verified triangular wave generator
http://www.electronicsproject.org/triangular-wave-generator/

Thank you, but i don't want to find a triangular wave form that can be easy if you google it
i need to know what's wrong with my circuit
i have attached the file again
here you are

 

[MAAASD]

hello again,
I still need your help

 

[expert_vision]

I'm trying to simulate the same type of triangular wave generator in Proteus and it fails to find a solution for the circuit, as well.