Thanks Ste. Finally a 555 circuit that works.
I was a bit surprised that changing the battery voltage did not change anything in the simulator, and then discovered it had an extra (hidden) spice parameter.
I replaced it with a battery with RefDes V1 and a value of “DC 15”, in the same way as in the video linked by paru.
Now I also noticed the pdf of Rohit_Kumar.
I see at least 2 errors in the pdf.
First. You have to annotate the schematic, so the question marks in the RefDes’s go away.
Then Voltage sources (such as your battery) need to have a Refdes starting with “V”, or the simulator will not recognize it as a voltage source.
For an estimate of simulation time constants. Take some ball park figure for a RC constant, and divide that time with a factor of at least 10. (50 to 100 or so is usually better, higher resolution often just adds more simulation time) For example, you have a 150k resistor on Q with a capacitor of 4.7uF.
1.5e5 * 5e-6 = 7.5 e-1
Which is just below a second, so simulation resolution should be well below 100ms resolution. Starting with 10ms is probably better.
Note that too high a resolution just slows down simulation, while a too coarse a resolution completely *&^%$#@! the whole simulation and the results do not make sense anymore.
In the screenshot below the resolution clearly is too low.
The output pulse widht (red) is not stable anymore, and the voltage over the timing capacitor (green) becomes chunky.