Electronic – Is it possible to pass netlist via command line to ngspice instead of using input file

Here is an excerpt from chapter 15 of the user manual which I found on sourceforge:

If ngspice is started in interactive mode (see chapt. 16.4.2), like

ngspice circuitfile.cir

and no control section (.control ... .endc, see 16.4.3) is provided in the circuit file, the dot commands are not executed immediately, but are waiting for manually receiving the command “run”.

Chapter 16 is full of all kinds of useful information about invoking ngspice from the command line. You should probably read chapter 16. I found it here: http://ngspice.sourceforge.net/docs/ngspice-manual.pdf

When in doubt, read the manual.

The solver will first try to find a solution, and the lack of initial conditions and the DC voltage will turn your circuit into a static analysis due to the lack of dynamics. Try these few changes, instead (either one at a time, or combinations):

• Make the voltage source a pulsed one, to mimic a step change at the beginning, something like PULSE(0 220 0 1u 1u 1k 2k).
• Add initial conditions to nodes with .ic V(<...>)=0, or
• ...add the initial condition to the capacitor, if the program allows, for example C1 4 0 2m ic=0.
• Add uic to the simulation card.

This last one overrides the forst three, it literally tells the solver to consider that the Universe is only starting when you press "run", so all initial conditions, everywhere, are zero.