B Muthuswamy and B Boser mbharat cory eecs berkeley edu EECS Department UC Berkeley Summer 2007 SPICE MultiSim Tutorial 1 Introduction Cellular phones and computers are just two examples of some of today s extremely complex electronic systems Such devices contain millions of circuit components and simple trial and error is not an effective way of ensuring that the final product will work properly As a result designers often use circuit simulators to verify the performance of a circuit before fabrication The most popular component level circuit simulator available today is called SPICE Simulation Program with Integrated Circuit Emphasis which was developed here at the University of California Berkeley in the 1970s under the guidance of Prof Pederson Today vendors offer many different versions of SPICE that differ mainly in the user interface but are internally very similar to the original Berkeley SPICE This tutorial introduces a version of SPICE called MultiSim Circuit simulation with SPICE and MultiSim involves two steps 1 Enter in the circuit schematic with MultiSim s graphical user interface 2 Choose the type of analysis and run the simulation 2 Organization of this Tutorial 1 Introduction 2 Organization I Basic Circuit Simulation Techniques in MultiSim 3 MultiSim Environment 4 Schematic Capture of an Example Circuit 5 Simulation and Results Display II Alternative Forms of Circuit Simulation in MultiSim 6 Simulated Instruments 7 Using the Breadboard Tool 8 Conclusion Notes about this Tutorial Before running a simulation you should always have a general understanding of how your circuit works In this document Boldface black refers to actions you perform on the computer Example Click on the menu item B Muthuswamy and B Boser mbharat cory eecs berkeley edu EECS Department UC Berkeley Summer 2007 3 MultiSim Environment 1 First you need to log into a lab machine to use MultSim Ask the TA in charge for login information You may also be able to use MultiSim by logging in remotely 2 Once logged in Double click on the icon on the desktop If a window appears with Evaluation License written in the middle of it click the Evaluate button After MultiSim finishes loading you should see the screen shown below in Figure 1 This is called Capture and Simulate environment because you Capture your schematic by drawing it in MultiSim and then you Simulate it Figure 1 also shows the different parts of the MultiSim workspace the location of the toolbars in your MultiSim window may be different Figure 1 The most important components in the MultiSim workspace The purpose of each toolbar will become clear as you move through this document If you don t see the toolbars shown above click on the View menu and go to Toolbars Make sure that you at least have the toolbars shown in Figure 2 checked B Muthuswamy and B Boser mbharat cory eecs berkeley edu EECS Department UC Berkeley Summer 2007 Figure 2 Viewing the toolbars 4 Schematic Capture Entering a Simple Circuit To begin let s construct the simple circuit shown below in Error Reference source not found This circuit is composed of a voltage source battery a resistor and a potentiometer variable resistor B Muthuswamy and B Boser mbharat cory eecs berkeley edu EECS Department UC Berkeley Summer 2007 Figure 3 A simple circuit captured in MultiSim I Adding the Voltage Source Battery 1 Click on the Power Source Family in the Virtual Toolbar 2 The Power Source Components will pop up 3 Click on the DC Power Source icon and then click on the workspace to place a battery Error Reference source not found shows the result Figure 4 A DC power source in MultiSim To change the value of the power source Double click the battery This opens up the Power Sources dialog box shown below Make sure that the voltage is set to 12 V and then press OK B Muthuswamy and B Boser mbharat cory eecs berkeley edu EECS Department UC Berkeley Summer 2007 Figure 5 Power Sources Dialog box Use this to change the value of the battery voltage II Adding the Resistor and the Potentiometer 4 Click the Basic Components Family 5 The Basic Components up in the Virtual Toolbar will pop 6 Click on the Virtual1 Resistor tool and drag a resistor onto the workspace Like the battery you can double click the resistor to change its properties 7 Lastly we must add the potentiometer In the Basic Components window click on the Potentiometer Tool and drag a potentiometer onto the workspace You can increase decrease the resistance on the potentiometer by pressing a Shift a on the keyboard The increase and decrease refers to the resistance between the middle leg and the bottom leg of the potentiometer You can also double click the potentiometer to open its properties and change the total resistance of the potentiometer or its increment decrement value Error Reference source not found shows the circuit components placed on your workspace The 50 next to the potentiometer means that the resistance between the middle leg and bottom leg is 50 of 1 k 500 If you press a the resistance will increase by 5 the resistance between the middle leg and the top leg will decrease by 5 Again you can Double click the potentiometer to change the increment percentage If you move your mouse over the potentiometer you can also use the slider that appears to change its resistance 1 MultiSim distinguishes Virtual components from Real components With real components you place a part that has the actual shape of the real component not a schematic symbol You will see examples of this in Section 8 B Muthuswamy and B Boser mbharat cory eecs berkeley edu EECS Department UC Berkeley Summer 2007 Figure 6 The circuit components are in place III Adding the Ground 8 The final component to add is the ground You cannot simulate the circuit without a ground because SPICE the underlying simulation engine uses nodal analysis to solve circuits The first step in nodal analysis is to pick a ground node It does not matter where we ground the circuit but for consistency let s pick the node at the bottom of the circuit as ground 9 Click the Ground tool in the Power Source Components menu Drag the ground to the bottom of the circuit the result is shown in Error Reference source not found Figure 7 Circuit ready for wiring 10 Connections are placed by clicking on the terminal of the first component moving the cursor the the target and clicking again Error Reference source not found shows the results of wiring the 12 V source to the 1 k resistor B Muthuswamy and
View Full Document
Unlocking...