[AMPS] Re: SPICE model

[Ian White, G3SEK]

John T. M. Lyles wrote:

>Thanks for posting the SPICE analysis for 3-500Z arc over, Ian. There 
>are folks who poo-poo SPICE models (such as Bob Pease, the National 
>Semiconductor guy), 

Like any other model, they'll let you down if you trust them too much.
Having been involved in computer modeling (literally from atomic to
global scale) for about 30 years, I've made most of the possible
mistakes... and hopefully learned something from them.

>but I belive that they have value in transient 
>analysis such as this, as long as inductances and capacitances of 
>strays are included as best as they are known. 

Or if you don't know them well, vary the values to see how important
they are. FWIW, those comments about grid transients were only made
after about 20 runs, trying different values for all the components to
see which ones were important and which ones weren't.

>We use them all the 
>time nowadays early in design stage of projects. I am still 
>struggling with modelling huge capacitor banks that are series 
>parallel, when one cap shorts out.

Now that does look like hard work!

73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)
                           http://www.ifwtech.com/g3sek

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