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Interface Overview

Installation, Requirements and Activation

Simply run SIMBA.exe on any modern Windows PC. A one-time activation process that requires an internet connection is required.

Interface Overview

At its heart, SIMBA is a circuit simulator. Like many other circuit simulators, SIMBA adopts a common user interface and layout of a Design and Library explorer on the left, showing all of the designs and models you have access to, a circuit editor in the center and a property panel on the right.

Interface Overview

The interface of SIMBA is divided into three main tabs:

  • Test Bench
  • Design
  • Result

Design Tab

The design tab is the center of your modeling experience.

Design Explorer

In SIMBA, a single project file can contain multiple designs, results, and test benches.

In the Design Explorer, use the Add Design button to create an empty design or the dynamic menu to Duplicate, Rename, or Delete an existing design. The Top-Left < button hides the explorer.

Design Explorer

Circuit Editor

Add and Move Models

Simba Model Libraries contains dozens of electrical, mechanical, and control models. To add a model to a circuit, simply double-click on it in the Library explorer or use the + button.

Add a model

To move a model, simply drag and drop it. Moving devices keep connections.

Move Model

Rotation and flip options are available when a device is selected.

Move Model

Connect Models

To connect models, click on a pin and drag the mouse while holding the left mouse button to the destination.

Connect models

It is also possible to use the + button available when a connector is selected.

Add Connection

Disable / Enable

It is possible to enable and disable devices by clicking the corresponding button in the context menu. Disabled devices are greyed out and are excluded from the simulation.

Add Connection


Labels can be used to connect different parts of a circuit without using connectors. To add a label, simply select a connector and click on the Label button.

Labels are also available in the Utility library.

Scopes and Parameters

The Properties panel on the right-hand side lists the parameters and scopes of selected models. It is possible to select multiple models to change their parameters at once.

Add Connection

Model parameters syntax

Model parameters can now use metric units and mathematical expressions.


Accepted suffixes are:

Suffix Coefficient
p 10E-12
n 10E-9
u or µ 10E-6
m 10E-3
k 10E3
M 10E6
G 10E9

Simple Mathematical expressions can also be used in parameter evaluations. Expression

Basic operators (+, -, *, ^, !), constants (pi, e...) and math functions (sin,cos...) are supported.


Expression are evaluated when simulation starts and a Syntax error is thrown if it can't be processed.


It is possible to define variables that can be reused in device parameter expressions.


Variable File

At the top circuit level, it is also possible to define additional circuit variables through a variable file.

The syntax is pretty simple:

  • Comments are defined with //
  • Variables are defined with the syntax : variable_name = variable_expression
  • Expressions supports S.I. units (p,n,u,m,k,M) and mathematical expressions and functions (Ex: M = A * cos (X))


Result Tab

The result tab allows the user to handle simulation results with different features:

  • select simulation results to display different charts through the result list located on the left-hand side of the tab;
  • manage different zoom options, display time cursors, perform a Discrete Fourier Transform (DFT) and export the chart with the toolbar located on the right-hand side of the tab.

Add Connection

Select simulation results

Simulation results are listed on the left-hand side of the simulation result tab. The "top-one" with the pin symbol always points to the last simulation and the result display will automatically refresh after a new simulation is run.

To overlay different curves, option single vertical axis of the toolbar can be selected.

Add Connection

Add different charts

Use the button New Chart to add a new chart below an existing one.

Add Connection

Zoom options

Different zoom options are available (shorcut in brackets):

Add Connection

Add Connection

Display cursors

One or two cursors can be activated providing x and y values and other information such as:

  • the minimum, maximum, peak-to-peak (P2P) values between the two cursors,
  • the mean and RMS values over the time period between the two cursors.

Add Connection


It is possible to manually set the cursor position directly in the cursor measurement panel.


By holding down the shift key, the distance between the two cursors is maintained while moving a cursor.

Perform a Discrete Fourier Transform (DFT)

The DFT calculation performed in SIMBA is the Goertzel algorithm applied to each frequency to get a list of DFT (Discrete Fourier Transform).

Two modes are available to perform this Discrete Fourier Transform:

  • Frequency steps: the user defines the first frequency (the fundamental), the number of harmonics to calculate and the number of periods to consider,
  • Time range: the user defines the minimal and maximal time of the window to consider and the number of harmonics to calculate.

DFT menu

Frequency Steps mode

In the Frequency Steps mode, the DFT settings are defined with the following parameters:

  • Main frequency (in Hz): the frequency of the fundamental for the DFT calculation,
  • Number of analysed period: defines the number of periods to scan,
  • Number of harmonics: defines all the calculated frequencies (fmax = Main frequency * Number of harmonics)

Minimal and maximal time (in s)of the considered window are calculated from the other settings:

  • Max time is the last simulation point,
  • Min time is defined to have a width of Number of analysed period / Main frequency.

Time Range mode

In the Time Range mode, the DFT settings are defined with the following parameters:

  • Min time (in s): the left border of the analysed window.
  • Max time (in s): the right border of the analysed window.
  • Number of harmonics: defines all the calculated frequencies (fmax = Number of harmonics / (Max time - Min time)).

In this mode, the Number of analysed period is 1 and the Main frequency is defined as 1 / (Max time - Min time)


If the cursor mode is activated, Min time and Max time are derived from the position of the cursors: One cursor: Min time is the cursor position and Max time is the last simulation point, Two cursors: Min time is the postion of the left cursor and Max time is the position of the right cursor.

DFT settings

Algorithm considerations

To give precise results, a DFT requires a sampled signal. The DFT algorithm will first resample the signals to a specific calculated sampling time. The sampling time is defined for each calculated frequency as follow:

  • the average time step is calculated (Simulation length / Number of calculated points),
  • we limit this sampling time between 64 and 2048 points per period (at the considered frequency) to ensure a good balance between precision and efficiency,
  • we limit the sampling time to the minimum time step (from the simulation).

Filter and Edit Signals

The filter control allows you to filter Results and Signals by Name.

Click on the 'Edit' Button to update the name and the color of the selected signal.


Type 'X' to filter only selected signals.

Filter and Edit Signal

Import an external .csv file

The result view allows to import .csv result files from other software into SIMBA.

SIMBA supports two different .csv formats:

  • "Single Time Column Format": the first column of the .csv file is the time, the others are the different measurements,
  • "Multiple Time Column Format": each odd column is the time, each pair column is a specific measurement.

To add a new chart using an external .csv file, click on the button - - next to the filter view, choose the desired csv format and select the file to load. It will create a new chart with all the signals from the .csv file.

Import .csv file menu


Authorized format for the .csv files:

Test Bench Tab

Test benches include various parametric analysis and model characterization tools. Test benches are designed to automate operationsthe modeling and simulation of power converters. Single parameter sweep are currently available. More test benches will be added soon.

Split View

The 'Split View' option available in the main menu (CTRL+T) splits the window in two showing simultaneously a design and its simulated waveforms.

Split View

Subsystems and User-Defined Libraries

Circuit can be simplified by grouping models into subsystems. Subsystems are stored in User-Defined Libraries bound to a project.

To create a new library, use the button on the top-right corner of the Libraries explorer. To create a new subsystem, use the New Subsystem button.

Create Subsystem

To edit a subsystem, simply use the Open button. When editing a subcircuit, the Pins library is available. Pins are typed (Electrical, Control, and Mechanical) and are used to interface subsystems.

Edit Subsystem