Excuse me sir but how could you separate each waveform just like that. When I run it, just I was not enabled to seperate them just as you did...hi,
Your teacher is incorrect it saying that Va,b,c and the currents ia, ib ,ic can be determined in using LTS, without knowing Va,b,c.
The actual values of ia,ib,ic depend upon the applied voltages Va,b,c
If Va,b,c are 0V then Vout of the OPA is also 0V.
If you wish, ask him to contact me and explain how he can solve this without Va,b,c.
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View attachment 225533
I'm very new to hear that "the OPA is saturated" term. I could not understand that what does this lead to?hi,
That is not good, the OPA is saturated, the Va,b,c are much to high a value.
Dont forget the OPA has Gain of 1+(50k/10k) = ~6
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Now I see my fault and you just made me truly happy by giving these further examples to clarify that term. I don't know how to thank you but really now I understood the importance and the real meaning of the Vout..hi,
The Vout of an OPA is limited by the supply voltages plus the limitations of the OPA to get close to the supply voltages.
So yours with a~5Vout means the OPA cannot go as high as you expected.
eg:
a 0.5Vinp would give 3Vout
a 1.5Vinp would want give a 6Vout but it cannot, it would be 5Vout max.
Also most common OPA's will only go between +/-1V of the supply voltages
So set Va.b.c around 0.1V
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Update:
To get get multiple plot panes.
Right click on the plot, from the pop up Menu select 'Add Plot Pane'
no no you explained way clear for it. Finally, I understood that thing ^^hi,
You have to use the .meas ure command
or
Right click on the plotted label and a drop menu will show select one cursor, look at these clips.
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It is not practical to teach you this way how to use the LTS functions.
Ah, that's just a perfect video for the measurements ^^
Ah, I just lived that moment when sir ericgibbs clarified my questions on this op-amp design ^_^Sorry but I fear the OP, even if getting the correct values and consequently, correct results, would end having no idea of what is going on in the divider on the NI input. Much more in his benefit would be if he manages to calculate the input voltage as determined by the three voltages on the three resistors, by hand.
In my quest to learn the basics of op amps, once I got that clear, it became my eureka moment. Sure, LTSpice was not then available, at least to me.
One last question is my teacher also said this and I could not understand it here:hi,
You have to use the .meas ure command
or
Right click on the plotted label and a drop menu will show select one cursor, look at these clips.
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It is not practical to teach you this way how to use the LTS functions.
Thank you very much for sending me this video.hi,
Your teacher means, use pencil and paper with your calculator to solve the problem values.
Watch this video, good teacher.
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Hi again, I found Ia Ib and Ic with reversed signs:hi,
Your teacher means, use pencil and paper with your calculator to solve the problem values.
Watch this video, good teacher.
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I just wanna ask that in the future as an engineer, can it be any problem to find those directions reversed just like that?hi c,
In LTSpice the current direction can be shown the 'wrong' way to what you would expect.
Your answers are very close to correct values as shown by LTS.
Look at this plot and ask any questions you may have.
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Please Post your asc file.
Omg thank you so much, finally, I've learned to do this trick on ltspice, I'm considerably a lot happy now ^^hi c,
Unzip this MP4.
Right Click on wire of interest.
E