Difference between revisions of "Ngspice/C2/DC-Sweep-Analysis/English-timed"
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Latest revision as of 18:48, 23 March 2017
Time | Narration |
00:01 | Welcome to this spoken tutorial on DC sweep analysis in Ngspice. |
00:07 | In this tutorial, we will learn: |
00:09 | To perform DC sweep analysis and Nested DC sweep analysis. |
00:14 | Basic knowledge of electronic circuits is a prerequisite for this tutorial. |
00:19 | Basic knowledge of Ubuntu Linux and shell commands is also required. |
00:25 | Ubuntu 12.04 is the operating system used with ngspice version 23 installed. |
00:33 | We will use the example circuit shown. |
00:36 | The circuit consists of three prominent nodes- 1, 2 and 3. |
00:40 | In addition, a fourth node called as reference OR datum node must be marked as node “0”. |
00:47 | This is mandatory for any circuit. |
00:51 | Let us open the ngspice netlist file "example.cir" corresponding to the circuit schematic shown before, in the text editor. |
01:00 | I have already opened this file in gedit text editor. |
01:04 | Note that netlist file is saved with ".cir" extension. |
01:10 | We can see all the components like voltage source, resistors and information about nodes connecting them together. |
01:18 | dc command included in the netlist file is used to perform dc sweep analysis. |
01:25 | General form to use dc command is as shown: |
01:29 | dot DC SRCNAM VSTART VSTOP VINCR |
01:35 | where |
01:37 | SRCNAM is name of independent voltage and current source. |
01:42 | VSTART, VSTOP and VINCR are the starting, final and increment values respectively, for the source. |
01:51 | As you see, we are sweeping voltage source V1 for a single value of 24 VOLTS with the step increment of 1. |
02:02 | Now, we will simulate this circuit and find out voltage values at different nodes. |
02:08 | Let us open ngspice through terminal. |
02:11 | Press Control, Alt, T together. |
02:14 | This will open the Terminal window. |
02:18 | Now I go to the folder where the netlist file, example.cir, is saved. |
02:23 | I do this as follows: |
02:26 | cd downloads path to the folder and press Enter. |
02:33 | Now, let us simulate the ngspice file. |
02:36 | Let us see how this can be done. |
02:39 | On terminal,Type: ngspice space example.cir and press Enter. |
02:51 | Value of voltage v1 is 2.4 volts. |
02:56 | Value of voltage v2 is 9.746 volts. |
03:01 | Other node voltages are also displayed. |
03:05 | Next we will see how to do nested dc sweep analysis. |
03:10 | Generalized form for this is as shown. |
03:14 | Dot DC SRCNAM VSTART VSTOP VINCR SRC2 START2 STOP2 INCR2 |
03:24 | where |
03:26 | SRCNAM is the Primary sweep variable and SRC2 is the Secondary sweep variable. |
03:33 | Secondary sweep variable forms the outer loop. |
03:36 | That is, for every increment of secondary sweep variable, the first sweep variable is stepped through its entire range of values. |
03:45 | It will be more clear with the example circuit we will simulate. |
03:50 | We will use Bipolar junction transistor based circuit in common base configuration. |
03:56 | Primary sweep variable is voltage Vin, connected between emitter and base terminals. |
04:03 | Secondary sweep variable will be the load resistor 'Rload'. |
04:08 | We will plot output voltage versus input voltage, for different values of the load resistor. |
04:14 | The output voltage is the voltage across Rload and the input voltage is Vin. |
04:21 | Following is the netlist corresponding to the common base transistor circuit. |
04:26 | NPN is the default model used for transistor "mod1", in the circuit. |
04:33 | As you can see, 'Vin' is varied from 0.2 volts to 2 volts with step increment of 0.02 volts. |
04:45 | Rload is varied from 5 kilo-ohms to 10 kilo-ohms with step increment of 2 kilo-ohms. |
04:53 | For different values of Rload, Vin is swept through the complete range of 0.2 to 2. |
04:59 | Graphs of output-voltage versus input-voltage is plotted in each case. |
05:05 | Plot v of 3 comma 4 plots the voltage drop between the nodes 3 and 4, that is the voltage across Rload. |
05:15 | Now, we will simulate this circuit and see the results. |
05:19 | On the terminal, type: source space example nested.cir and press Enter. |
05:35 | This will run the simulation. |
05:37 | source command is used to simulate the netlist from within the ngspice simulator environment. |
05:44 | As you can see, graph of output-voltage versus input-voltage is plotted for different values of load resistor. |
05:52 | Quit the ngspice simulator by typing "quit" and press Enter. |
05:59 | Here, we come to the end of this tutorial. |
06:02 | In this tutorial, we learnt: |
06:04 | To perform- DC sweep analysis of a given circuit. |
06:08 | Nested DC sweep analysis of a given circuit. |
06:12 | Watch the video available at the following link. |
06:14 | It summarizes the Spoken Tutorial project. |
06:18 | If you do not have good bandwidth, you can download and watch it. |
06:22 | The Spoken Tutorial project team: |
06:24 | Conducts workshops using spoken tutorials. |
06:27 | Gives certificates for those who pass an online test. |
06:31 | For more details, please write to:contact at spoken hyphen tutorial dot org |
06:37 | Spoken Tutorial is a part of the Talk to a Teacher project. |
06:41 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
06:47 | More information on this mission is available at: |
06:51 | spoken hyphen tutorial dot org slash NMEICT hyphen Intro |
06:58 | Thank you for joining. Hope you found this tutorial useful. |
07:02 | This is Anuradha Amrutkar, signing off. |