excellent explanation, but I get this error "unknown subcircuit n002 n001 VCC 0 Vout ua741". I tried your lesson step by step several times. Version is 24.0.9
Can you explain to me how you got the term R3/R1 in the expression for vo? I tried to combine two expression for the voltage dividers R1, R2 and R3, R4, but that doesn't work. So I'm doing something wrong. Can you help me?
Thank you. The detailed theoretical analysis of the circuit considered in this video is available in this video here: ruclips.net/video/YX_X2vilisY/видео.htmlsi=qEvXCy2MTLLf3o9-&t=300
@@electriccircuits7164 Dear sir, I looked at the link you provided to me. And it made me perfectly clear how you derived the expression for vo, which you use in this video. Thank you very much.
Thank you for the question. I am not sure what you mean by "derivatives". If I understand it correctly, NO you do not need to change the op-amp model every time you use the 741 op-amp in a new schematic.
This is a common error which has been reported by some other viewers. See other comments in this video. It arises when the symbol has not been properly created and linked. Please carefully follow all the instructions in the video from 4:03 onwards. The subcircuit file must be placed in the correct folder where LTSpice can find it. See the path indicated in the video description.
@@electriccircuits7164 Hello Sir, I was able to run the simulation, I cross checked it with the values you have shown in the video and my simulation values are matching with what you have shown. Your tutorial is on point. Yes I am using the new version. I was making the following mistakes. 1) Did not save the uA741.lib file. 2) I was not careful while using lower & upper case. 3) Symbol (.asy file) not saved at proper location
Thank you for sharing the detailed post. It should help anyone else with common mistakes to avoid! I am glad you were able to successfully troubleshoot!
The ua741 subcircuit is below. Copy paste this subcircuit in a uA741.lib file. Place this subcircuit file in the folder
C:\Users\[USERNAME]\Documents\LTspiceXVII\lib\sub
--------------------------------------------------------------------
* Source: qucs.sourceforge.net/docs/tutorial/opamp.pdf (page 62)
*-----------------------------------------------------------------------------
* connections: non-inverting input
* | inverting input
* | | positive power supply
* | | | negative power supply
* | | | | output
* | | | | |
.subckt uA741 1 2 3 4 5
c1 11 12 8.661E-12
c2 6 7 30.00E-12
dc 5 53 dx
de 54 5 dx
dlp 90 91 dx
dln 92 90 dx
dp 4 3 dx
egnd 99 0 poly(2) (3,0) (4,0) 0 .5 .5
fb 7 99 poly(5) vb vc ve vlp vln 0 10.61E6 -10E6 10E6 10E6 -10E6
ga 6 0 11 12 188.5E-6
gcm 0 6 10 99 5.961E-9
iee 10 4 dc 15.16E-6
hlim 90 0 vlim 1K
q1 11 2 13 qx
q2 12 1 14 qx
r2 6 9 100.0E3
rc1 3 11 5.305E3
rc2 3 12 5.305E3
re1 13 10 1.836E3
re2 14 10 1.836E3
ree 10 99 13.19E6
ro1 8 5 50
ro2 7 99 100
rp 3 4 18.16E3
vb 9 0 dc 0
vc 3 53 dc 1
ve 54 4 dc 1
vlim 7 8 dc 0
vlp 91 0 dc 40
vln 0 92 dc 40
.model dx D(Is=800.0E-18 Rs=1)
.model qx NPN(Is=800.0E-18 Bf=93.75)
.ends
The procedure described takes effect only if "ua741" is replaced by "uA741". This is so because the name of the subcircuit is actually "uA741".
Yes that is correct. I will add a note to the video description about the lower/upper case sensitivity.
excellent explanation, but I get this error "unknown subcircuit n002 n001 VCC 0 Vout ua741". I tried your lesson step by step several times. Version is 24.0.9
Thank you for the feedback. It may be that the op-amp model file is not placed in the correct location. Hence, it is giving unknown subcircuit error.
Can you explain to me how you got the term R3/R1 in the expression for vo? I tried to combine two expression for the voltage dividers R1, R2 and R3, R4, but that doesn't work. So I'm doing something wrong. Can you help me?
Thank you. The detailed theoretical analysis of the circuit considered in this video is available in this video here: ruclips.net/video/YX_X2vilisY/видео.htmlsi=qEvXCy2MTLLf3o9-&t=300
@@electriccircuits7164 Dear sir, I looked at the link you provided to me. And it made me perfectly clear how you derived the expression for vo, which you use in this video. Thank you very much.
thank you for the tutorial! do I need to change the derivatives everytime I use it in a new schematic?
Thank you for the question. I am not sure what you mean by "derivatives". If I understand it correctly, NO you do not need to change the op-amp model every time you use the 741 op-amp in a new schematic.
i am getting an error ... unknown subcircuit ua741 called in ... wht could be the error here ...
You have to create and add the ua741 model in LTSPICE. Please carefully follow all the instructions in the video from 04:03 onwards.
i am getting an error. (Could not open include file " ua741.lib")
This is a common error which has been reported by some other viewers. See other comments in this video. It arises when the symbol has not been properly created and linked. Please carefully follow all the instructions in the video from 4:03 onwards. The subcircuit file must be placed in the correct folder where LTSpice can find it. See the path indicated in the video description.
@@electriccircuits7164 I have placed the symbol in the library specified in component top directory. Yet I am getting the same error.
Thank you for reporting this. Are you using the latest version of LTSpice?
@@electriccircuits7164 Hello Sir, I was able to run the simulation, I cross checked it with the values you have shown in the video and my simulation values are matching with what you have shown. Your tutorial is on point.
Yes I am using the new version.
I was making the following mistakes.
1) Did not save the uA741.lib file.
2) I was not careful while using lower & upper case.
3) Symbol (.asy file) not saved at proper location
Thank you for sharing the detailed post. It should help anyone else with common mistakes to avoid! I am glad you were able to successfully troubleshoot!