ngspice in KiCad 8: oscillators, taming an astable

Oscillators are sometimes difficult to simulate, they don't have a stable operating point (astable ...), they sometimes, depending on the device models, oscillate with difficulty, or the simulator finds a stable operating point, and then the oscillation does not start. In this video some means to get around these issues are presented.

[@PreludeSon]

Such a great tutorial, really appreciated this

[@peatmoss4415]

The only reason this circuit oscillates is because of the variance of tolerances of the components. If you pair the transistors and capacitors and resistors it won't oscillate unless you take a wire and short a couple of legs of the transistors for a split second. (or discharge one capacitor and charge the other) This is a sample circuit in electronics training. In that one, an LED is placed above the collector of the transistors. This simulation might have a random variable in the algorithm to resemble the variances in component manufacturing. TinkerCad is another simulation online.

[@ivolol]

How could one learn on their own that to get a better representation for certain simulations they can change an integration method from "trap" to "gear" (both terms I have no clue about)? Would you just have to get really lucky in a google search?

[@holger8105]

My (old school) advice would be: grab a book about SPICE simulation. A list of books is given here: ngspice.sourceforge.io/books.html . I would recommend the book by Tadej Tuma , Árpád Buermen. Also the book by Kielkowski directly answers your question. Hopefully there is a library near your place which offers such technical books.