Re: help about a SPICE model

From: Winfield Hill (hill_a_at_t_rowland-dotties-harvard-dot.s-edu)
Date: 03/21/05 

Date: 21 Mar 2005 06:23:40 -0800

jeko wrote...
>
> Mike Monett ha scritto:
>> jeko wrote:
>>
>>> I must use SPICE 3f5 Berkeley version on linux system.
>
> Thank you, but I'm obliged to use only SPICE 3f5 (3f2 or higher)
> on linux system. :(

 Most of us like to use Spice programs that have a graphical front
 end and back end. This means we can enter the schematic, check
 the viability of the models, tell it to run the included Spice 3F5
 or whatever, engine, and display the results in graphical plots.
 Some of these are available in free versions that are sufficiently
 powerful to run your simple circuit. For example, the Intusoft
 Spice CD or download that's available free at On Semiconductor.
 http://www.onsemi.com/site/content/0,4367,1270,00.html
 http://www.intusoft.com/ONSemiconductor.htm

 But it's not hard to simply use the free spice engine by itself
 and enter your spice program by hand. You must already have the
 syntax manual for standard spice. If not, it's easy to find.

 Number the nodes of your circuit and type in the drawing, line
 by line for each component's connections. The only thing you'll
 be missing is an opamp model. A number of possibilities are open
 to you. Such as, pick some common opamp, and get its model from
 the manufacturer's website. It'll probably be a variant of the
 Boyle model. Study the model to see how it works, and modify it
 for the specs of your problem.

 For simple problems I sometimes like to make a basic opamp from
 a VCCS and a VCVS with a capacitor to ground between them to
 create the opamp's gain rolloff, plus a series output resistor...
 it's worth playing with anyway. Go, and simulate your day away.
 And of course you can come back to us with more questions. 

-- 
 Thanks,
    - Win
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