[sdiy] Spice beginner / Quadrature oscillator

[Tim Stinchcombe]

Hi Karl,

> The damned thing most of the time refuses to oscillate,

Don't know how to do it in LTSpice, but stick an 'initial condition'
somewhere in the circuit, perhaps on one of the caps  - if you don't the 'dc
operating point' analysis will 'exactly balance' the circuit, and all you'll
get is a flat line. An initial condition will destroy this 'balance', and
make the caps charge/discharge as we want them to, so it will then
oscillate. In SIMetrix, I have made C3 start at 1V, and it works a treat!
I'm sure placing an 'IC' on a cap is a SPICE thing, so it's just a matter of
finding out how to do it in LTSpice -  probably just open up some dialogue
box associated with caps/the specific cap?

> the 
> one time i've gotten it to it's giving me triangle outputs 
> instead sine/cosine.

Triangle waves is what it is giving me, at a frequency of nearly 48Hz, which
I'm supposing is exactly what it is meant to be!

Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk
www.timstinchcombe.co.uk