Ngspice/C2/Operating-point-analysis-in-NGspice/English-timed

Time	Narration
00:01	Dear Friends, Welcome to this spoken tutorial on “Operating point analysis" in NGspice.
00:08	In this tutorial, we will learn:
00:10	To perform operating point analysis
00:13	To verify Kirchoff's voltage law, using ngspice in- interactive mode command-line interface and commandscript included in netlist file.
00:24	Ubuntu 12.04 is the operating system used with ngspice version 23 installed.
00:33	Basic knowledge of electronic circuits is a prerequisite for this tutorial.
00:38	Basic knowledge of Ubuntu Linux and shell commands is also required.
00:43	We will use the example circuit shown.
00:47	The circuit consists of three prominent nodes-
00:52	a,
00:53	b
00:55	and c.
00:57	In addition, a fourth node called as reference or the datum node must be marked as node “0”.
01:06	This is mandatory for any circuit.
01:09	Let us open the ngspice netlist "example1.cir" file, corresponding to the circuit schematic shown before, in a text editor.
01:19	I have already opened this in gedit text editor.
01:27	Note that the netlist file is saved with ".cir" extension.
01:32	We can see all the components like voltage source, resistors and current source.
01:41	Also, the information about nodes connecting them together.
01:46	".op" command, included in netlist file, is used to perform operating point analysis.
01:54	Now we will simulate this circuit and verify Kirchoff's voltage law using the interactive mode-command-line interface.
02:02	Let us open ngspice through terminal.
02:06	Go to top left corner of Ubuntu desktop screen.
02:10	Click on theDash home.
02:13	In the search bar, write "terminal" and press Enter.
02:22	This will open Terminal window.
02:26	Let me resize this window.
02:30	Now, I will go to the folder where the netlist file "example1.cir" is saved.
02:38	I do this as follows:
02:40	On terminal, I will type: cd space Desktop slash op hyphen analysis and press Enter.
02:55	Now, let us simulate the ngspice file.
02:59	Let us see how this can be done.
03:01	On terminal, type: ngspice space example1.cir and press Enter.
03:17	Here, you will notice that we have entered into the ngspice command line interface.
03:23	Type: "run" and press Enter.
03:28	This will simulate the circuit and store the results.
03:33	We will verify Kirchoff's voltage law using the above simulation results.
03:39	According to Kirchoff's voltage law, voltage around outer loop should be equal to the value of the dc voltage source V1.
03:51	Calculate voltage around the outer loop.
03:54	For this, let us do the following:
03:59	In the ngspice command line interface, on the terminal,
04:03	type: print space v of a comma b plus v of b comma c plus v of c and press Enter key.
04:21	Here, v of a comma b denotes the voltage drop between the nodes 'a' and 'b' and so on.
04:29	print command displays the results of the calculation mentioned to its right side.
04:36	Notice the result of the calculation on the terminal.
04:39	It is 30 volt as shown.
04:42	Now, calculate the value of DC voltage source V1 that is v(a).
04:50	Type: print space v of a and press Enter.
05:00	Notice the result of the calculation on the terminal.
05:04	If both the results are equal then Kirchoff's voltage law is verified.
05:10	Since both voltage values are equal, the Kirchhoff's Voltage law is verified for outer loop- a, b, c and 0.
05:21	Now, we will simulate this circuit and verify Kirchoff's voltage law, using the command script included in the netlist file.
05:31	Modified netlist file example hyphen modified dot cir is as shown.
05:40	As you can see, all the commands we executed in command-line interface are included in this netlist as control statements.
05:50	That is, the statements in between the dot control and the dot endc statements.
05:57	Echo command will echo the text written to its right side, on the terminal window.
06:04	You can see that we have included the print statements in the netlist.
06:10	Now, we execute the modified netlist file.
06:14	source command is used to simulate the netlist from within the ngspice simulator environment.
06:22	On the terminal, type: source space example hyphen modified dot cir and press theEnter key.
06:37	This will run the simulation and directly show the results for KVL verification.
06:43	You can see that results are the same as seen earlier.
06:48	This brings us to the end of this tutorial.
06:52	Quit the ngspice simulator by typing quit and press the Enter key.
07:00	Now, let us summarize what we learnt in this tutorial.
07:03	In this tutorial, we learnt-
07:05	* To perform operating point analysis of a given circuit.
07:09	* To verify Kirchhoff's voltage law using ngspice through interactive mode-command line interface , command script included in the netlist file.
07:20	Watch the video available at the following link.
07:24	It summarizes the Spoken Tutorial project.
07:28	If you do not have good bandwidth, you can download and watch it.
07:32	The Spoken Tutorial project team:
07:34	* Conducts workshops using spoken tutorials.
07:38	* Gives certificates for those who pass an online test.
07:41	For more details, please write to:contact at spoken hyphen tutorial dot org
07:47	Spoken Tutorial Project is a part of the Talk to a Teacher project.
07:52	It is supported by the National Mission on Education through ICT, MHRD, Government of India.
07:59	More information on this mission is available at:
08:02	spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
08:09	Thank you for joining.
08:11	Hope you found this tutorial useful.
08:13	This script is contributed by Abhishek Pawar and this is Rupak Rokade from IIT Bombay, signing off.
08:19	Thank You.

Contributors and Content Editors

Madhurig, PoojaMoolya, Pratik kamble, Ranjana, Sandhya.np14