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LT Spice Assistance...

Gryd3

Jun 25, 2014
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Well... I'm working on a circuit for a member on the Forums, and am already getting stuck...
I've built a portion of : http://makezineblog.files.wordpress.com/2010/10/ledcolororgan-schem_r1.gif

I am measuring the signal along the portion of the light organ that I built and the OPamps are not behaving like I had assumed...
I feed a 600mV Audio signal in, and I only get a 6nV signal out from U2... The resulting signal at the final output is many many magnitudes smaller than the input.

Any ideas on what I am missing?
 

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KrisBlueNZ

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Nov 28, 2011
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Yeah :) In LTSpice, megohms must be written "meg". Otherwise it assumes you mean milliohms! It doesn't distinguish "m" from "M".
 

KrisBlueNZ

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Yeah, that's a real trap for young players. It should be written large on the first help page!
 

Gryd3

Jun 25, 2014
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Still some quirks I'm not used to.. like trying to find components.. I couldn't find a 555 timer, but it's in there as an 'NE555'
I'm having issues now trying to install a shift register XD
 

KrisBlueNZ

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Yeah. It doesn't come with much as standard - just the stuff that Linear Technology know you'll need to simulate their products. There's a Yahoo group where files are posted and archived though. If you need a specific part you can often find it there.
 

Harald Kapp

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Nov 17, 2011
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In the ressources section I have put some useful stuff for LTSPICE, including how to include models for components that are not delivered as parts of LTSPICE's deployment.
All you need is find the spice model. Many manufacturers offer them for download.

A shift register is a digital part. While LTSPICE has the capability to simulate digital components in a rudimentary way, it is still an analog simulator, not a digital one. There are better simulators for that purpose.
 
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