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OPA square wave generator, single supply OPA is not working

 
Edited

LT1006 was a single supply OPA. Trying and gathered no output when single supply was used. welcome any hints or experience would be share, thanks.

the code used,
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[Mod note:? schematic code deleted]
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Edited

Please don't post such long netlists. Few of us will try to help using a netlist. Upload your .ASC file AND all the other files required to run the simulation, but not .RAW? and .LOG files or pictures,? in a ZIP archive to Files => Temp.

Go to the web page: /g/LTspice/topics. Click on Files in the list on the left. Then click on Temp. Then click on New Upload in the blue box at top left. Click on Upload File in the drop-down menu. Then send a message to tell us that you did that.

On 2025-05-04 09:02, wai wai via groups.io wrote:
LT1006 was a single supply OPA. Trying and gathered no output when single supply was used. welcome any hints or experience would be share, thanks.

the code used,
?
?
[Mod note: Edited for brevity]
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion

Virus-free.

 

wai wai,
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I have edited your message to remove the nonsense schematic that you attached to your message.? DON'T EVER DO THAT!
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Go back and read (actually read!) the instructions about using this group.? Notice where it says:
Important:? Do not attach?or include or embed or drag-and-drop any files or pictures in your messages.? Instead,?upload?files to this group's "Temp" folder -
Now, if you want help, upload your schematic file to the group's Temp folder.? Then tell us that you uploaded a file there.
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You almost did the right thing earlier today, by uploading a schematic (humidity_sensor.asc), but then you deleted it!? Why?
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I also deleted your schematic text because it has an unrecognizable character which even LTspice can't use.? That might have been caused by attaching your schematic code to a message.? Instead, UPLOAD the file, which preserves the characters.
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Andy
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Edited

wai wai,
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The schematic you attached to your message today has several mistakes.? I am just letting you know.? It was a very sloppy schematic and you should not have used it as an example.
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Apparently the question was about the LT1006.? But your schematic also has three other op-amps, which are apparently unrelated to the question, and you forgot to connect any power to those op-amps.? Without power, they can not operate.? Leaving inoperable circuits on the same schematic can cause problems with the simulation.? It might even have caused the oscillator to not oscillate (although that was not the reason in this case).
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You used multiple net names on the same nets.? That is unwise and should be avoided.? Nets (wires) can have only one net name.
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The comment on your schematic asked:
LT1006 is single supply OPA
but single 5V has no square wave oputput
dual power supply vcc & vee must be, why ?
The answer to that question is because your circuit is wrong.? It does not oscillate because the voltage on the "voltage" "vcharge" net (across the capacitor) never drops below the voltage at the R7/R6 junction, when the op-amp drives Low.? That voltage must become lower in order for the op-amp's output to go High, which it can never do.? The circuit has a stable operating point when the amp's output is Low.
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You must re-arrange the bias conditions of your circuit to make it oscillate with a single supply.? The LT1006 op-amp is operating correctly.
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Andy
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Oops - correcting a typo.? I wrote:
It does not oscillate because the voltage on the "voltage" net (across the capacitor) ...
but that should have said:
It does not oscillate because the voltage on the "vcharge" net (across the capacitor) ...
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Andy
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On Sun, May 4, 2025 at 04:11 AM, wai wai wrote:
LT1006 was a single supply OPA. Trying and gathered no output when single supply was used. welcome any hints or experience would be share, thanks.
Suggestion:
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Connect the bottom end of R7, to a voltage which is between VEE and VCC.? That allows the voltage across the capacitor to ramp above and below that voltage.
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By connecting the bottom end of R7 to VEE itself (to a grounded negative supply), the voltage across the capacitor is unable to swing to both sides of it, which is necessary for it to oscillate.
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Andy
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I uploaded "LT1006 oscillator.zip" to the Temp folder.? It has three schematics:
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  • "Original (corrupt!).asc" is the original schematic that wai wai attached to a message.? It is corrupt, probably because it was attached to a message.
  • "Fixed the corrupt values.asc" is the same except that I substituted the "mu" or "micro" character (?) for each instance of the corrupt character, hopefully restoring the original values.
  • "Just the fixed oscillator.asc" is the same schematic but with the three other op-amps and all their unrelated circuitry removed, and with one change to the oscillator's biasing, which makes it oscillate with either dual or single supplies.
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Why was the original file corrupt?? (Sorry, long story ahead.)? LTspice uses the Greek letter "mu" (?) to mean micro.? By default, if you have a capacitor, inductor, or resistor with a value in micro-anything - even if you physically type a "u" - LTspice converts it to a mu (?).? (You can disable that if you like, in the Settings / Control Panel.)? That letter is represented by the single byte hex B5 (0xB5).? Some may think of it as if it was part of the ASCII character set, but it is not.? PCs with MS-Windows knew 0xB5 meant "?".
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All is well if those schematics stay within LTspice, and move to and from your computer's drive and most other drives.? But if you take the actual text code (of an LTspice .ASC schematic file) and open it or copy-and-paste it into a text editor, bad things might happen to it.? Some editors preserve it.? Others do not; they notice it is a non-ASCII character and attempt to convert it into something else, which might be either one or two bytes.? We saw that a lot before 2020 when this group was hosted on Yahoo!Groups, because Yahoo's editor would corrupt those bytes if anyone ever edited an LTspice schematic file that had been previously uploaded.
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In this particular case, when wai wai copied-and-pasted the contents of their original schematic file into their message for the group, those characters found themselves converted from ? to Ϥ and they were now corrupt and not recognized by LTspice.? (That is one of the reasons why you should never ever paste a schematic file into your messages in this group!)? I think LTspice interpreted the "1Ϥ" capacitor as a 1 (Farad) capacitor.? And similarly for the others.? Like all good SPICE programs, unrecognized multipliers are ignored.
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In the second file inside the .ZIP, I fixed those corrupt values.? I assumed that all six bad values were supposed to be microfarads.
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Most of the circuitry on that schematic was entirely unrelated to wai wai's question about the oscillator.? So I deleted it.? The third schematic has just the oscillator, with one small change so that it oscillates with either dual or single supplies.
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Andy
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thanks Andy. I am trying to learn LTspice and opa & this group for help at the same time of which may meet alot of new stuff. i ould try files/uploading later on.

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