Sine Wave Question - diyAudio
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 8th August 2012, 01:19 AM   #1
skidave is offline skidave  United States
diyAudio Member
 
skidave's Avatar
 
Join Date: Jul 2006
Location: York, Pennsylvania
Default Sine Wave Question

I just downloaded the latest version of LTspice and I am having an issue with generating a sine wave for a power supply I am simulating. I need to simulate a power transformer with 360 volt secondaries (for a tube amp). I'm missing something when I select a voltage source and set it for sine. The sine wave form is going from 0 to 360 (bottom half peak is at 0 and top is at 360). Why is it not showing the 0 reference in the middle of the waveform and displaying the negative half of the cycle in the negative numbers. I don't remember this in the earlier version I was using.

Am I missing something?

Thanks in advance.
  Reply With Quote
Old 8th August 2012, 06:33 PM   #2
RJM1 is offline RJM1  United States
diyAudio Member
 
Join Date: Jan 2010
Location: Titusville, Fl.
Do you mean something like this?
Attached Files
File Type: asc 360V.asc (305 Bytes, 14 views)
  Reply With Quote
Old 8th August 2012, 10:07 PM   #3
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
Voltage source setup tab, offset.
  Reply With Quote
Old 9th August 2012, 01:26 AM   #4
skidave is offline skidave  United States
diyAudio Member
 
skidave's Avatar
 
Join Date: Jul 2006
Location: York, Pennsylvania
Thanks for the replies. See attached and what is happening.

Where is the voltage source setup tab; is this the right click on the component to set the voltage?

I can't believe I'm missing this!

Draft AC.asc
  Reply With Quote
Old 9th August 2012, 01:27 PM   #5
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by skidave View Post
Thanks for the replies. See attached and what is happening.

Where is the voltage source setup tab; is this the right click on the component to set the voltage?

I can't believe I'm missing this!

Attachment 295255
Everything is OK, but your source is floating, and to see its voltage you must measure across it, not with respect to ground.
That's the same in real life anyway.

To measure across something, the easiest way is to left-click on what you consider as the "hot" node, and keeping the button depressed move to the cold node. This will give you something like Nxyz,Nabc.
You can also enter that expression manually in the trace name:
Attached Images
File Type: png Example.png (110.0 KB, 56 views)
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  Reply With Quote
Old 9th August 2012, 05:17 PM   #6
skidave is offline skidave  United States
diyAudio Member
 
skidave's Avatar
 
Join Date: Jul 2006
Location: York, Pennsylvania
Thanks Elvee! I just tried it and it works. Makes sense now because it is not ground referenced. As well, I did not know how to measure across a component...I do now.

On another note, I have noticed another circuit is not showing the RC time constant when you simulate it. Do I have to change something in the simulate command to show the cap charging? It just simulates with the cap at full voltage. I don't remember having this issue in version III.
  Reply With Quote
Old 9th August 2012, 05:31 PM   #7
macboy is offline macboy  Canada
diyAudio Member
 
Join Date: Oct 2003
Location: Ottawa, Canada
By default, LTSpice will determine the DC (steady state) operating point and simulate from there. If you want your power supplies to start with 0 volts, there is a checkbox for that in the edit simulation command window. You can also choose to skip the initial operating point solution.
  Reply With Quote
Old 9th August 2012, 06:01 PM   #8
skidave is offline skidave  United States
diyAudio Member
 
skidave's Avatar
 
Join Date: Jul 2006
Location: York, Pennsylvania
Thanks Macboy. I did find that and now it simulates properly.

Thanks everyone!

Dave
  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
Linn Lingo vs. Dr. Fuß or Square-Wave vs. Sine Wave Oscillator for Motor Control tiefbassuebertr Analogue Source 62 15th December 2013 10:23 PM
Sine Wave Generator with bulbs (Sine-lightenment) Rodeodave Everything Else 6 21st July 2008 12:19 PM
Sine wave - Square & Triangle wave generator using Transistors / OP-Amps lineup Solid State 20 9th October 2006 12:15 AM


New To Site? Need Help?

All times are GMT. The time now is 10:59 AM.


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