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Your circuit is too complex... It was working until I added the op amp
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MaskNerd 3 days ago
I'm new at this, so please forgive me if I have overlooked rookie mistakes that could be found on the forum... This "Sine/Square Wave Oscillator" circuit (I don't need the square waves) was taken from "IC Timer Cookbook" pp 203-204, by Walter Jung Pub 1977. And yes, I'm that old, bought it when it came out ;-) It's now online as a .pdf here: [http://vtda.org/books/Electronics/ICTimerCookbook1stEd1977_WalterGJung.pdf](http://vtda.org/books/Electronics/ICTimerCookbook1stEd1977_WalterGJung.pdf) I modelled the "Minimum Component Astable" on page 116 first, and the simulation worked fine after switching to the pulse supply someone recommended to kick-start the timer (that did the trick). The op amp was selected using shift-F, as was the 555 timer and all the resistors and capacitors. I did get some help regarding the 'too complex' issue, but I still am not getting what I should get for the output... see my comments below. I could use some more guidance, here. Much appreciated. Here is the link to my project:  [https://easyeda.com/MaskNerd/sine-wave-oscillator-2](https://easyeda.com/MaskNerd/sine-wave-oscillator-2) is the link for examining the topic. ... in the share box I found this link also, and I don't know what it is: [https://easyeda.com/editor#id=5f0bd2761fc64a618ef14ea5eb3ccc46](https://easyeda.com/editor#id=5f0bd2761fc64a618ef14ea5eb3ccc46)
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andyfierman 3 days ago
Welcome to EasyEDA. Before posting in the forum, please ensure that you have read: [https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a](https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a)<br> <br> and the documents that it links to as this will answer most of the questions that new users post here in the forum. It will also help you get the most enjoyment out of using a new tool with the least frustration. Your project is private so only you can see it. The steps to make a project public and share the link to it are given in the Tutorial and also here: [https://easyeda.com/forum/topic/How-to-make-a-Project-public-and-share-the-links-to-it-9f006513b84b412580910905b0281d20](https://easyeda.com/forum/topic/How-to-make-a-Project-public-and-share-the-links-to-it-9f006513b84b412580910905b0281d20)<br> <br> You may like this: [http://www.designinganalogchips.com/_count/designinganalogchips.pdf](http://www.designinganalogchips.com/_count/designinganalogchips.pdf)<br> <br> from the late Hans Camenzind's site: [http://www.designinganalogchips.com/](http://www.designinganalogchips.com/)<br> <br> <br> <br>
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andyfierman 2 days ago
The link you posted to your project does not work. Is this it? [https://easyeda.com/MaskNerd/sine-wave-oscillator-2](https://easyeda.com/MaskNerd/sine-wave-oscillator-2)
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andyfierman 2 days ago
Part of the problem is that you have set R2 and R11 to milliOhms instead of MegOhms. In spice, m = M = 1e-3 Meg = meg = 1e6 :)
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andyfierman 2 days ago
If you set the stop time to 10ms, your sim will run. Try running your sim for say 10ms and then increase the stop time  in steps.
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andyfierman 2 days ago
Yup, if you set: 1. .tran 100m 2. R2 = 2.2Meg 3. R11 = 3.3Meg then your sim runs fine. Nice circuit! I've not seen it before. :)
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MaskNerd 2 days ago
@andyfierman YES! I couldn't find anything in the tutorials (or forum discussions that complained that 'Your project is private') that said exactly what link to share, so, as a newbie. I chose, to me the most likely option being the one that showed a url. NOW I know. Don't know how you found it, but thanks!
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MaskNerd 2 days ago
@andyfierman M vs. m. Thanks! Now, What is K vs. k? kilo and Kinko? ;-) Thanks again for your help, VERY much appreciated.
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andyfierman 2 days ago
To get up to speed in using simulations in EasyEDA, you need to read the Simulation Tutorial, (3) in (2) in: [https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a](https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a)<br> <br> The **About naming conventions** section includes the scale factors.
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MaskNerd 2 days ago
OK, well... yes, it does run, but the only thing I can get is a series of unstable output - a series of near-square waves that fail to be sustained, and the 555 has to re-trigger the circuit and start over. You said 'Nice circuit! I've not seen it before.' Is this what you got as well? Or were you able to get a continuous sine wave output? Coming from the well-known book I find it hard to believe the circuit would not work. Also, after spending maybe 4 hours playing with the component values, I have given up making it perform as expected. For the most part, making even minor value adjustments results in the 'too complex' failure to compute. Is this a fundamental limitation of the spice simulation capabilities, or am I still missing something? I will be VERY much appreciative if you can help me further. -Curtis
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MaskNerd 2 days ago
By the way, apparently [https://easyeda.com/MaskNerd/sine-wave-oscillator-2](https://easyeda.com/MaskNerd/sine-wave-oscillator-2) is the link for others whou would like to examine the topic.
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MaskNerd 2 days ago
One confusing observation is how the output of the op amp goes to 15V when the power supply is only + 12VDC. The positive input is biased to 6VDC, and the negative volt connection to the op amp is at ground potential. When playing with the component values, I sometime observed the output swing to -4VDC. How are these swings above and below the power supply potentials possible?
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andyfierman 2 days ago
@MaskNerd, Sorry but you're not reading my notes or the Simulation Tutorial properly: you have still set R2 as 2.2M and R11 as 3.3M. Spice is not case sensitive so **M** is the same as **m** and means 1e-3. You want MegOhms not milliOhms. So R2 must be written as 2.2**Meg** or 2.2**meg** or 2.2e6 and R11 must be written as 3.3**Meg** or 2.2**meg** or 2.2e6. You cannot write a 2.2 MegOhm resistance as 2.2m or 2.2M because that is 2.2 milliOhms or 2.2e-3 Ohms! This is why I insist that people must read the all of the Simulation Tutorial before attempting to run simulations in EasyEDA. It just saves so much pain for everyone.
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andyfierman 2 days ago
@MaskNerd, And this is what you get if you set the right resistor values (I tidied up the schematic for clarity): ![image.png](//image.easyeda.com/pullimage/z0DBeJl5MFSvVbw4p3gMCIgGO5vnrJpPgpdnuKYy.png) Which generates (ignore the XY cursor readout): ![image.png](//image.easyeda.com/pullimage/a7pP56vQtPuBfu3yUXDNAlkqo3WKpZnuvi2JydMv.png) And if you replace the oscilloscope with voltage probes with user-friendly names: ![image.png](//image.easyeda.com/pullimage/y3t0l7725SlltyMipR18WGzistTz0AElgJMJWUSS.png) then you get this slightly more comprehensible plot: ![image.png](//image.easyeda.com/pullimage/AxdZiZ5mdyL4PUn0iP9BVTZfCurF8BdfqKIbLMB1.png)
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MaskNerd 2 days ago
@andyfierman Thanks! and I confess I only read what seemed (to me) what was relevant.
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