Difference between revisions of "Ngspice/C2/Operating-point-analysis-in-NGspice/English-timed"

|'''Time'''

|'''Narration'''

| Dear Friends, Welcome to this '''spoken tutorial''' on “'''Operating point analysis'''" in NGspice.

| 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.

| '''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''', '''b'''

| 00:55

| and '''c'''.  

| 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'''.

| We can see all the components like '''voltage source, resistors''' and '''current source'''.

| Also, the information about nodes connecting them together.

| ''' ".op" command''', included in netlist file, is used to perform '''operating point analysis'''.

| Now we will '''simulate''' this circuit and verify '''Kirchoff's voltage law''' using the '''interactive mode-command-line interface.'''

| Let us open '''ngspice''' through '''terminal.'''  

| Go to top left corner of '''Ubuntu''' desktop '''screen.'''

| In the '''search bar,''' write "'''terminal'''" and press '''Enter.'''

| This will open '''Terminal window.'''

| Let me '''resize''' this window.

| Now, I will go to the folder where the netlist file "'''example1.cir'''" is saved.

| On terminal, I will type: '''cd space Desktop slash op hyphen analysis ''' and press '''Enter.'''

| Now, let us '''simulate''' the ngspice file.  

| On terminal, type: '''ngspice space example1.cir''' and press '''Enter.'''

| Here, you will notice that we have entered into the '''ngspice''' '''command line interface'''.

| Type: "run" and press '''Enter'''.

| This will '''simulate''' the circuit and store the results.

|  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   

| 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'''.

| Notice the result of the calculation on the terminal.

| 05:04

| 05:10

| Since both voltage values are equal, the '''Kirchhoff's Voltage law''' is verified for outer loop-  a, b, c  and 0.

| Now, we will '''simulate''' this circuit and verify '''Kirchoff's voltage law''', using the '''command script''' included in the netlist file.

| Modified netlist file '''example hyphen modified dot cir''' is as shown.

|  As you can see, all the commands we executed in '''command-line interface''' are included in this '''netlist''' as '''control statements.'''

| That is,  the statements in between the '''dot control''' and the '''dot endc''' statements.

| '''Echo''' command will '''echo''' the text written to its right side, on the '''terminal window.'''

| Now, we execute the modified '''netlist''' file.

| '''source''' command is used to '''simulate''' the '''netlist''' from within the '''ngspice simulator environment'''.

| On the terminal, type: '''source space example hyphen modified dot cir''' and press the'''Enter''' key.

| This will '''run''' the '''simulation''' and directly show the results for '''KVL''' verification.  

| Quit the '''ngspice simulator''' by typing '''quit''' and press the '''Enter''' key.

|  Now, let us summarize what we learnt in this tutorial.

| In this tutorial, we learnt-

| To verify '''Kirchhoff's voltage law''' using '''ngspice''' through '''interactive mode-command line interface ''', '''command script''' included in the '''netlist''' file.

| Watch the video available at the following link.

|  It summarizes the '''Spoken Tutorial''' project.

| If you do not have good bandwidth, you can download and watch it.

|  The Spoken Tutorial project team:

|Conducts workshops using spoken tutorials.

| Gives certificates for those who pass an online test.

|  For more details, please write to:'''contact at spoken hyphen tutorial dot org '''

| '''Spoken Tutorial''' Project is a part of the '''Talk to a Teacher''' project.

| It is supported by the National Mission on Education through ICT, MHRD, Government of India.

| More information on this mission is available at:

| '''spoken hyphen tutorial dot org slash NMEICT hyphen Intro'''.

| This script is contributed by Abhishek Pawar and this is Rupak Rokade from '''IIT Bombay''', signing off.