Ngspice/C2/Operating-point-analysis-in-NGspice/English-timed
From Script | Spoken-Tutorial
Title of the Script: Operating point analysis using ngspice
Author: Abhishek, IIT Bombay
Keywords: video tutorial, ngspice.
| Time | Narration |
|---|---|
| 00:01 | Dear Friends, Welcome to the 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, |
| 00:17 | interactive mode command-line interface & |
| 00:21 | 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, |
| 01:37 | resistors |
| 01:39 | 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 |
| 02:18 | 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 |
| 02:52 | 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, |
| 03:03 | Type ngspice space example1.cir |
| 03:13 | 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, |
| 03:41 | 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 interfaceOn the Terminal , |
| 04:03 | Type print space v of a comma b plus v of b comma c plus v of c |
| 04:18 | 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 |
| 05:16 | a |
| 05:17 | b |
| 05:18 | c |
| 05:19 | 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 |
| 06:33 | 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 |
| 06:58 | 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 . |
| 07:17 | commandscript included in thenetlist 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. |
