From: Jim Thompson
Subject: Re: Another SPICE problem!
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Date: Thu, 09 Jan 2003 18:14:03 GMT
NNTP-Posting-Date: Thu, 09 Jan 2003 13:14:03 EST
Organization: Cox Communications
On Thu, 09 Jan 2003 16:18:47 +0000,
Paul Burridge ,
In Newsgroup: sci.electronics.cad,
Entitled: "Another SPICE problem!",
Wrote the following:
|Just working through an example circuit of a common emitter amplifier
|from the Roberts and Sedra SPICE handbook. The circuit uses bypass and
|coupling capacitors all of the value 1GF - a ridiculously high value
|contrived to enable the effects of bandwidth attenuation at low
|frequencies to be eliminated from the simulation runs. Problem being,
|when I run the sim, I get a 'time-step too small' error message. On
|looking this up, one of the suggested remedies was to "make the
|circuit more realistic" so the obvious thing to do was to change the
|cap values to something more appropriate to the real world. I chose
|100uF all round. Result: works perfectly. So why does Roberts and
|Sedra expect one to be able to run a simulation that won't work with
|the suggested values?
Did you ever know a professor that was connected to the real world
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| Jim-T@analog_innovations.com Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
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