View source for Ngspice/C2/Operating-point-analysis-in-NGspice/English-timed

'''Title of the Script:''' Operating point analysis using ngspice

'''Author:''' Abhishek, IIT Bombay

'''Keywords: '''video tutorial,''' '''ngspice. 

{| border=1 
!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 the'''Dash 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''' in 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''' in 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 the'''Enter 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 ''', '''commandscript''' included in the '''netlist''' file.

|-
|  07:20
| Watch the video available at the following link 

|-
|  07:24
|  It summarises 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.

|}