Go Back   Home > Forums > Design & Build > Software Tools

Software Tools SPICE, PCB CAD, speaker design and measurement software, calculators

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 17th June 2013, 08:38 PM   #1
diyAudio Member
 
Join Date: Mar 2007
Location: California
Default HELP: TINA model of oscillator using 4093 not working. Desperate!!!

I'm trying to model a circuit that has a few 4093 NAND Schmitt triggers in it. I can't seem to figure out how to get the model working in TINA (Spice modeler from TI). I've seen the exact circuit modeled elsewhere on the web just fine, so I am really at my wits end here. I haven't modeled any logic circuits before now, so it could definitely be user error, but I am stumped.

PLEASE HELP!

Circuit and output are attached. It's right out of the datasheet! It should be a free running multivibrator but nothing is happening. I've included a timed switch so that pin 1 is pulled down to zero initially - that datasheet shows the transition low to high in case that was the source of the problem, but still nothing.

-Charlie
Attached Images
File Type: gif 4093 oscillator not working.GIF (23.0 KB, 51 views)
  Reply With Quote
Old 17th June 2013, 09:01 PM   #2
diyAudio Member
 
Join Date: Mar 2007
Location: California
Ahhhhrrggggh. OK, I figured it out. I was simulating the circuit using the condition "zero initial values", which seemed to me to be the case since the circuit is "off" prior to simulation. If I just changed this to "use initial conditions" the circuit simulates as expected. Oddly enough, I haven't actually included any initial conditions for the circuit! How great is that, huh.

Anyway, now that I have much less hair remaining on my head, this annoyance has been solved.
  Reply With Quote
Old 2nd July 2013, 11:48 PM   #3
diyAudio Member
 
Join Date: Apr 2011
Location: Pretoria
Yep, that cap needs to get charged to get the oscillator going.
  Reply With Quote
Old 2nd July 2013, 11:57 PM   #4
diyAudio Member
 
Join Date: Mar 2007
Location: California
Quote:
Originally Posted by ingenieus View Post
Yep, that cap needs to get charged to get the oscillator going.
No, the initial charge up wasn't the problem. No matter how long the sim time frame, there were no oscillations. As long as I used "zero initial values" it would not sim correctly. As soon as I switched to "use initial conditions" it worked as expected.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
6S4/6S4A TINA-TI/SPICE model? fhs Software Tools 10 10th May 2012 06:27 AM
Amp switching with 4093/4066. How to add indicator LEDs? soma_hero Tubes / Valves 3 20th January 2010 01:57 AM
I am desperate for help with my amp seafire Solid State 24 25th November 2009 03:42 AM
Use of a Ribidum Oscillator as refrence oscillator in a DAC Mark A. Gulbrandsen Digital Line Level 18 2nd January 2009 09:57 PM


New To Site? Need Help?

All times are GMT. The time now is 12:00 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2