NI Multisim

• User Interface• Schematic capture

‒ Creating the File‒ Placing a Component‒ Wiring the Circuit

• Simulation – Analysis– The Grapher– Virtual Instruments– The Postprocessor

• Reports

User Interface

1) The Menu Bar is where you find commands for all functions.

2) The Component toolbar contains buttons that you use to select components from the Multisim databases for placement in your schematic.3) The Standard toolbar contains buttons for commonly-performed functions such as Save, Print, Cut, and Paste.

4) The Main toolbar contains buttons for common Multisim functions.

User Interface

7) The Simulation toolbar contains buttons for starting, stopping, and other simulation functions.

6) The In Use List contains a list of all components used in the design.

5) The Place probe toolbar contains buttons that you use to placevarious types of probe on the design. You can also access Probe settingsfrom here.

User Interface

10) The Instruments toolbar contains buttons for each instrument.

8) The Circuit Window (or workspace) is where you build your circuit designs.

9) The View toolbar contains buttons for modifying the way the screen is displayed.

User Interface

11 Scroll Left/Right 12 Workspace 13 Spreadsheet View 14 Active Tab

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The Spreadsheet View allows fast advanced viewing and editing of parameters including component details such as footprints, attributes and design constraints. You can change parameters for some or all components in one step and perform a number of other functions.

Simulation: Analysis

Multisim offers many analyses, all of which use simulation to generate thedata for the analysis you want to perform.

For each analysis, you will need to decide upon some settings that will tellMultisim what you want the analysis to do.

In addition to the analyses provided by Multisim, you can also create user-defined analyses based on SPICE commands you enter.

When you activate an analysis, the results are displayed on a plot in theMultisim Grapher, unless you specify otherwise, and saved for use in thePostprocessor.

To indicate that an analysis is running, the Simulation Running Indicatorappears in the status bar as shown in the figure below. This indicator flashesuntil the analysis is complete.

Simulation: Analysis

To perform an analysis:1. Select Simulate»Analyses and simulation.2. A menu appears with the list of analyses available.3. Select the desired analysis. Depending on the

analysis selected, a dialog box appears.

Interactive simulation• This mode performs a time-domain simulation (transient analysis) until you

click the Stop button. In this mode, data is displayed by the instruments and bythe indicator components.

• You can also place probes to display measurements directly on the circuit duringinteractive simulation.

• Additionally, interactive components such as switches and certain instrumentssuch as the Function Generator, can be used to change the circuit state duringsimulation

• You can use interactive simulation by clicking on the Run/ResumeSimulation button .

Simulation: Analysis

Analysis parameters Initial Conditions drop-down list—Select one of:

• Zero, • User-Defined, • Calculate DC Operating Point, or • Automatically Determine Initial Conditions (Multisim tries to start the

simulation using the DC operating point as the initial condition. If the simulation fails, it uses user-defined initial conditions, which by default are set to 0).

End time (TSTOP) field-End time of transient analysis must be greater than start time.

Maximum timestep (TMAX) is the maximum time step the simulation can handle. When Checkbox is not checked the program generates time steps automatically. Thicked checkbox enable to manually set time steps.

Initial time step (TSTEP) checkbox—Enable to set the initial time step for simulation output and graphing

Simulation: Analysis

DC Operating Point AnalysisIt determines the DC operating point of a circuit.

AC SweepIt performs phasor/complex analysis of the circuit across a range of frequencies. Itis useful for analyzing the frequency response of a circuit.

• DC sources are given zero values.• AC sources, capacitors, and inductors are represented by their AC models.• Nonlinear components are represented by linear AC small-signal models,

derived from the DC operating point solution.• All input sources are considered to be sinusoidal. The frequency of the sources

is ignored.

AC Analysis then calculates the AC circuit response as a function of frequency.

Simulation: Analysis

Frequency Parameters of the AC Analysis dialog box:

• Start frequency (FSTART)—The start frequency for the sweep.• Stop frequency (FSTOP)—The stop frequency for the sweep.• Sweep type—The sweep type: decade, linear, or octave. Defines how

points to be calculated are distributed across the frequency range.

Simulation: Analysis

Simulation: AnalysisTransient analysis (also called time-domain transient analysis)• Multisim computes the circuit’s response as a function of time.• Each input cycle is divided into intervals, and a DC analysis is performed for

each time point in the cycle.• The solution for the voltage waveform at a node is determined by the value of that

voltage at each time point over one complete cycle.

Set the Transient Analysis parameters using the:• Initial Conditions drop-down list. Select one of the following condition to

Determine Initial Conditions

• Start time - Must be greater than orequal to 0 and less than End time.

• End time - Must be greater thanStart time.

• Maximum time step button - Clickto enter the maximum time stepthe simulation can handle.

If you have the oscilloscope connected to your circuit and activate the circuit, asimilar analysis is performed.

The result of the transient analysis is a calculation of voltage versus time.

Simulation: The Grapher

This tool is used to display all of the Multisim analysis in graph form.

This graph can be edited, saved, and exported

To access the grapher first run the simulationClick view > grapher

Simulation: Virtual Instruments

Multisim offers several virtualinstruments which can be usedto simulate and analyze yourcircuit

Found in two places on the userinterface.

• Tool bar on the right hand side

• Click Simulate > Instruments

Simulation: Virtual Instruments - Oscilloscope

The oscilloscope instrument can bewired directly onto your circuit design.

To run the simulation click Simulate >Run or the green Run arrow

Double click on the oscilloscope graphicto show the dialogue box and output.

You can directly manipulate the interactivecomponents on the schematic with yourmouse.

Simulation: Virtual Instruments

Agilent Simulated Function Generator 33120A

This function generator is a 15 MHzsynthesized function generator with built-in arbitrary waveform capability.

• Standard Waveforms—Sine, Square, Triangle, Ramp, Noise, DC volts.• System Arbitrary Waveforms—Sinc, Negative Ramp, Exponential Rise, Exponential Fall, Cardiac.• User Defined Arbitrary Waveforms—Any type of waveform with 8 – 256 points.• Modulations- AM, FM, Burst, FSK, Sweep.• Memory Sections—Four memory sections named #0 – #3. #0 is the system default.• Trigger Modes—Auto/Single for Burst and Sweep modulation only.• Display Digital—4 – 8.• Display Voltage—Three modes: Vpp, Vrms and dBm.•Edit Digital Value—Change the displayed value with cursor buttons or number keys, or use the knob, or use the ENTER NUMBER key to key in the number directly.

Supported FeaturesMost of the features that are documentedin the Agilent 33120A User’s Guide areavailable in its virtual simulated version.These include:

Simulation: Virtual InstrumentsAgilent Simulated Oscilloscope

The simulated Agilent Technologies 54622D Oscilloscope is a 2-channel +16 logicchannels, 100-MHz bandwidth oscilloscope. Refer to the Agilent website for aPDF copy of this instrument’s user guide.

Simulation: The post processorUse the Postprocessor to manipulate the output from analyses and plot the results on a graph or chart. Types of mathematical operations that can be performed on analysis results include arithmetic, trigonometric, exponential, logarithmic, complex, vector and logic.

ReportsYou can generate a number of reports in Multisim: • Bill of Materials (BOM),

• Component Detail Report,

• Netlist Report,

• Schematic Statistics,

• Spare Gates and the

• Cross Reference Report.

BOMA summary of components withinthe design

Only lists “real” components(excludes virtual instruments)Click Reports > Bill of Materials