Introductory Electronics Laboratory - Circuit Simulators | EL ENG 43, Lab Reports of Electrical and Electronics Engineering

Download Introductory Electronics Laboratory - Circuit Simulators | EL ENG 43 and more Lab Reports Electrical and Electronics Engineering in PDF only on Docsity! SRR 2/9/2004 Page 1 EE 43 Circuit Simulators In this lab, we will explore computer software used to simulate electric circuits. We will use the PSpice educational suite, which is available for free download at http://www.orcad.com/downloads/demo/default.asp 1. Example Circuit Here is the circuit we will simulate in this lab exercise. 10 kΩ 15 kΩ 20 kΩ 25 kΩ12 V 2 mA Use nodal analysis (by hand) to find the voltage at each node with respect to ground. This goes into your lab report. 2. Creating a Circuit Graphically PSpice Capture allows you to enter a circuit into the PSpice simulator graphically. From the Start Menu, within Programs, go to the PSpice folder and select Capture. Click on the “New” icon or go to File -> New -> Project. Name the project whatever you like. From the options, choose “Analog or Mixed A/D”. This will load all the part libraries you need. Finally, choose your working directory and click OK. A window with grid points will appear; this is where you will draw the circuit to be simulated. To make your life easier, change the preferences so that the circuit SRR 2/9/2004 Page 2 elements you place are aligned with the grid. To do this, go to Options -> Preferences -> Grid Display and make sure “Pointer Snap to Grid” is checked in both cases. 2a. Placing Parts Now you are ready to start placing the parts of your circuit. Each circuit element has a name in PSpice—and there are hundreds of them. Go to Place -> Place Part and a window appears. (The toolbar on the right hand side also has a “Place Part” button.) The parts are organized into libraries depending on the type of part. To see what kind of parts PSpice has, highlight a library and a part--a picture of the part will come up. If you don’t see any libraries, ask your GSI. The parts we will need are: R in the library ANALOG resistor IDC in the library SOURCE ideal current source (constant current) VDC in the library SOURCE ideal voltage source (constant voltage) To place a part, select it, click ok, and stamp it on the schematic wherever you need it. To change the value, double click the value (if you double-click the symbol, you will get a confusing options screen). PSpice recognizes the following strings (case-insensitive) as powers-of-ten prefixes: p pico 10-12 t tera 1012 n nano 10-9 g giga 109 u micro 10-6 meg mega 106 m milli 10-3 k kilo 103 To change the name of the element, double-click the name. The parts are named automatically and you don’t have to change the names. 2b. Placing Wire and Ground After you have placed all the elements and set the values, you need to wire the circuit together. Go to Place -> Wire or click the wire icon on the toolbar at right. Click once to start a wire and click again to end it. The program will show a red circle when you connect to a wire or terminal. Once you have connected the circuit, you must tell the simulator where the ground node is—it uses nodal analysis to find voltages and currents in the circuit. Ground is also known as “node 0” in the simulator. To place ground, go to Place -> Ground or the ground icon on the toolbar at right. Choose 0 (zero) from the SOURCE or CAPSYM library. Place the ground and attach it with wire.