February 21, 2012

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Spice Up Your Circuits!
A Homebrewer's Overview of Circuit Simulation


Audio Recording ... (Listen to MP3 recording

Text Log from this week's session ...

<19:55:19>*** You are now talking in channel: "QRP Homebrewing"
<20:05:14>"Joe - N2CX": http://www.njqrp.org/teamspeak/Feb%2021.html
<20:07:06>"Dave AA3UR": Couldn't find K7QO's tutorial
<20:07:49>"Joe - N2CX": Dave do a web sEARCH FOR K7QO SPICE Tutorial
<20:08:06>"Dave AA3UR": yes, at google
<20:08:38>"Terry WB4JFI": The link at the bottom worked for me.
<20:09:30>"George - N2APB": Yep, the link is good at the bottom of the web page.
<20:10:12>"Dave AA3UR": Sorry was looking at a copy of the page from a few hours ago. AOK
<20:11:31>"George - N2APB": Yep, you gotta keep up with me!   (I update the page often, even during the session.)
<20:21:42>"George - N2APB": Main uses of Circuit simulation:
<20:21:46>"George - N2APB": DC Analysis
<20:21:56>"George - N2APB": Frequency Response
<20:22:31>"George - N2APB": Tweak comnponent values to affect the characteristic being looked at
<20:23:15>"George - N2APB": Transient reponse .. power on views, imact of changes in the circuit inputs
<20:25:19>"George - N2APB": Audio amplifier response
<20:27:10>"George - N2APB": Nic has used Electronic Workbench inthe past ... worked great, but it can't work on modern platforms
<20:27:30>"George - N2APB": EWB probably had even more capabilities than LTspice
<20:28:05>"Dave AA3UR": try running old software with DosBox.  It will even run win311 on current windows
<20:42:14>"George - N2APB": Pspice ... anyone use it?
<20:43:59>"George - N2APB": Started with Orcad and then purchased by Cadence.  There's a student version available online.  May have limited capabilities.
<20:59:42>"Terry WB4JFI": Another LTSpice tutorial at: http://pages.suddenlink.net/wa5bdu/ltguide.pdf
<20:59:59>"Terry WB4JFI": I just ran into it, not sure how good it is.  Terry
<21:00:14>"Al - N8WQ": enjoyed the topic, thanks Joe and George
<21:00:32>"Nic - KF5ADE": Thank you for putting this together

Session Notes ...

o Simulation Program with Integrated Circuit Emphasis

o Developed by ERL of the University of California at Berkeley began as open source software

o Means of setting up electronic circuits and examining how they work with computer computations.

o Develop circuit with mathematical descriptions of electronic components called models

o Apply analog stimulus – DC, AC, Transient

o Run nonlinear simulation program and examine voltages and currents around the circuit

o Originally used a “Netlist” to input the circuit.  R, C, L, transistors, diodes, sources 

o Ran program and asked for calculated outputs             

o Could now simulate electronic circuits without building them.

o Analyze performance and tweak almost real time to optimize.

o Automated worst case, temperature and component variation analysis


Circuit to Analyze:


o Netlist generation very tedious and not too intuitive.

o Modern programs use GUI for speed and easier understanding

o Still use component models hidden in menus

o Generate schematic with  built-in schematic capture program

o Shows circuit and all stimulus

o Outputs can be generated on screen or save to a file.



1.    SPICE wiki page:  <http://en.wikipedia.org/wiki/SPICE>

2.    Intusoft commercial program  <http://www.intusoft.com/>

3.    Electronics Workbench  commercial program <http://www.electronicsworkbench.com/>

4.    LTspice freeware from Linear Technology <http://www.linear.com/designtools/software/>

5.  LTspice user group on Yahoo <http://tech.groups.yahoo.com/group/LTspice/>

5.    WEBENCH - <http://www.national.com/en/power/electrical_simulation.html>

6.    WinSpice - <http://www.winspice.com/>

7.    K7QO SPICE Tutorial – http://www.k7qo.net/spice.pdf




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