Transformer/excitation coil for Armstrong oscillator

On Tuesday, September 25, 2018 at 9:00:34 PM UTC+5:30, Tim Williams wrote:
> <dakupoto@gmail.com> wrote in message 
> news:7d529c91-326c-4792-b646-98cb0c021df9@googlegroups.com...
> > I use Ngspice The netlist is below
> >
> <snip>
> 
> This is all backwards.  It's also not recommended to use SUBCKTs that don't 
> conserve current (i.e., they are all using the implicit global node 0 for 
> ground, instead of connecting it through a pin).
> 
> Compare the Armstrong circuit to the netlist, and doublecheck device pin 
> orders if necessary.
> 
> You also have unused PARAMs, which may be confusing.
> 
> Tim
> 
> -- 
> Seven Transistor Labs, LLC
> Electrical Engineering Consultation and Design
> Website: https://www.seventransistorlabs.com/

Well, I am not sure what you mean by "backwards". I have in 
the past used a dedicated ground pin for SUBCKTs both with
HSpice and Ngspice, but I do not think that made any obvious
difference in the performance.

On Tuesday, September 25, 2018 at 5:06:41 PM UTC+5:30, Steve Wilson wrote:
> On Tuesday, September 25, 2018 at 5:44:30 AM UTC-4, daku...@gmail.com wrote:
> > On Tuesday, September 25, 2018 at 1:11:19 PM UTC+5:30, Steve Wilson wrote:
> > > On Monday, September 24, 2018 at 6:29:25 AM UTC-4, daku...@gmail.com wrote:
> > > > Could some electronics guru on this group please help ? I am trying to set up a SPICE simulation for an Armstrong oscillator. The problem seems to be with designing the transformer and/or excitation coil. 
> > > > Are there any good tutorials or related material online. Any hints/
> > > > suggestions would be of immense help. Thanks in advance.
> > > 
> > > Should be easy. Assuming you are using LTspice, post your ASC file. I'll see if I can help.
> > 
> > I use Ngspice The netlist is below
> > 
> 
> Sorry, I use LTspice. I don't have time to translate your netlist.

That is fine. Both HSpice and Ngspice use text based input 
netlists, which allows for efficient and intuitive circuit design. For example, a few weeks ago at work I was using Hspice to do some crosstalk simulations with a basic configuration of
of 3 microstrip lines, where each microstrip line consists of 
1024 unit(series inductor, resistor, shunt capacitor, conductance) cells. Took me about 45 minutes to get the first
cut simulation running. I am absolutely sure it would have
taken me several hours with a GUI based simulator. I mean 
just wiring up the whole setup would have been a challenge. .