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Welcome to the NI Circuit Design Community

Welcome to the NI Circuit Design Community - a community and blog for NI Multisim users. This community is a forum for engineers, educators and students to share custom components, models and footprints, and collaborate with fellow circuit designers around the world. Join the group to get automatic updates from our circuit design blog.

Owned by: Mahmoud_W GarretF Fernando_D nestor Bhavesh

Tags: simulation, multisim, circuit, electronics, ultiboard, blog, design, ni, patterns, spice, workbench, prototype, pcb, components, models, footprints, land

Group Type: Members Only

Created: Feb 9, 2009

Custom Simulation Analyses

Download custom Multisim analyses at the Multisim Custom Simulation Analyses and Instruments Community

Getting Started

New to circuit design? The following resources step you thorugh the fundamental stages of prototyping.


  1. Capture and simulate
  2. Create a custom component
  3. Transfer to layout
  4. Routing a design
  5. Create a custom landpattern
  6. Complete design for fabrication
  7. Export to Gerber and NC drill
  8. Pre and post layout check-list


Use Multisim and Ultiboard to design with these resources.

Recent Blog Posts

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A fuse is a temperature sensitive device that plays a critical role in circuit protection. Since the operating temperature has an effect on fuse performance and lifetime, it is extremely valuable to be able to model fuse thermal derating in a SPICE environment while the operating temperature should be taken into consideration when selecting the fuse current rating.


This new model implements a very fast acting fuse that includes its thermal derating curve. Simulation will show how the operating current and temperature have an effect on the fuse’s performance and lifetime.


Fuse Model with Thermal Derating Parameters


The Multisim model is developed based on the approach introduced in this paper and is shown in Fig. 1. The implemented fuse model is for the 0603SFV050F/32-2 very fast-Acting chip fuses by TE Connectivity. The parameters used inside the models are as follows:

  • the rated current: irs=0.5A
  • the nominal cold DCR: RFref=0.860Ω
  • the nominal I2t: I2tref=0.0093A2sec

The model requires the fuse resistance at the end of the pre-arcing time, rfm, which is usually provided in the datasheet. This resistance can be determined through laboratory measurements. Another variant to determine the rfm is to consider that the heating process of the fuse is rapid and adiabatic. Knowing the fuse material, the fuse resistance at room temperature, RF, using equation (1), rfm can be calculated considering that the resistance versus temperature is linear:




where α is the temperature coefficient of the fuse material, Tm is the melting temperature of the fusing material, and T0 is the reference temperature. The length and section area of the fuse are considered constant.

The thermal derating curve is implemented using a lookup table, while the values above were taken from the fuse manufacturer datasheet. The variation of the fuse resistance with temperature and also the variation of the I2t in percent with temperature are all taken into account inside the model.



Figure 1. Fuse SPICE model internal structure


Note that in the model above the W2 current controlled switch is used for removing the path for Cfuse discharge after the fuse is blown. To view the model of the fuse double click on it and then click on the Edit Model button under the Value tab.


Running the Fuse Model


The fuse is placed in a simple test circuit (attached to the article) to verify its operation in an interactive simulation setup.



Figure 2. Test circuit setup



Figure 3. Load voltage during when over current passes through the fuse



The Parameter Sweep Analyses can be used, to show the fuse’s response at different currents. In the Analysis Sweep field, the Transient Analysis option must be chosen. Both the Transient and Parameter Sweep Analyses configurations are shown below in Figure 4.






Figure 4. Analysis setup in Multisim



Running this sweep analysis, the transient response of the fast acting sweep can be evaluated under different current conditions. This is valuable in determining how fast the fuse will melt and how much energy is needed to do so. The results are shown in Figure 5.




Figure 5. Analysis results in Multisim




Moreover, the effect of the ambient temperature could be analyzed in Multisim. It is important to understand how differently the fuse will behave at 75 degrees from a normal 25 degrees room temperature. For this purpose a temperature sweep from 25 to 125 degrees is setup in Multisim to run the same circuit under a constant load current.



Figure 6. Temperature sweep setup in Multisim



Figure 7. Simulation results of the temperature sweep



The ismulation results show that the higher the environment temperature is the faster the switch will respond to the over-current.


You can download this advanced fuse model and start using it in the attachment.


Clcik here to download a 45-day free evaluation of the latest release of Multisim.


NI Multisim is a powerful tool used to simulate and prototype power electronics circuit designs. Multisim has large database of configurable power component models along with existing SPICE models from various semiconductor manufacturers. The simulation capabilities in Multisim enable the evaluation of different power circuits of different ratings at an early design stage.


This is the first of a series of blog posts about new power electronics models specifically developed for simulations renewable energy applications in NI Multisim. The models were developed in collaboration with the Virtual Instrumentation and Renewable Energy Laboratory at the Transilvania University of Brasov in Romania.


In this article, three solar Photo-Voltaic (PV) cell models are presented:


1. Basic PV Cell

this model represents the ideal and most simplistic case of a PV cell model. the solar cell is modeled using an ideal current source in parallel with a diode and a load resistance.





The model is available in the Multisim file Testing the Solar Cell Modules_1.ms13 attached to this post. Connected to the model are two DC sources; Virrad representing the level of illumination where 1000V=1000W/m2 a, while Vbias allows the variation of the bias point to measure the output I-V characteristics. In a real world application, Vbias would be replaced by a load.



The internal parameters of the models are set based on a Si solar cell example:

  • The reverse saturation current (Io = 10-11 A)
  • The short circuit current (Isc = 0.034 A)
  • The area of the solar cell (A = 1cm2)


These parameters could be viewed and altered simply by double-clicking the component on the schematic and clicking on Edit model in the Value tab:


Running a DC Sweep simulation in Multisim to evaluate the output current at different bias points as well as the output power, the below graph could be reproduced






2. Advanced PV Cell with Series and Shunt Resistance

This model is based on the single exponential model published in [1]. It add a shunt and series parameters to model the panel resistance.


The same Si solar cell example was used to set the following parameters:

  • The constant material (B = 5.769*106 )
  • The short circuit current (Isc = 0.034 A)
  • The area of the solar cell (A = 1cm2)
  • The energy bangap (Eg = 1.11eV)
  • The series resistance (Rs = 0.1 Ω)
  • The shunt resistance (Rsh = 10000 Ω)


In this advanced model the open circuit voltage of the solar cell depends on the material of the solar cell expressed in the material constant B and the energy band gap Eg. The material constant can be determined using the variation of the reverse saturation current function of the temperature and it theoretically derives from this relation:


While the values of the energy Bandgap for some important semiconductor materials are available in the table below:


Semiconductor materials

Energy bangap [eV]














The model and the test circuit are available in the attachment Testing the Solar Cell Modules_2.ms13. Running a Nested DC Sweep yields the following I-V characteristics of the PV cell







3. Advanced PV Panel

This is a model of a PV panel based on a number of individual solar cells connected in series using one diode model with irradiance and temperature parameters. It is based on the physical parameters of the BP-MSX120 PV panel, however these parameters could be altered in the model to match other PV panels:

  • The short circuit current (Isc = 3.87 A)
  • The series resistance (Rs = 0.47 Ω)
  • The shunt resistance (Rsh = 1365 Ω)
  • The temperature coefficient of the power (kp = −0.5 ± 0. 05)
  • The number of solar cells in series (ns = 72)
  • The ideality factor of diode (A = 1.397)


The example testing circuit to validate this model is in the attached file Testing the Solar Cell Modules_3.ms13

A nested temperature sweep is performed to evaluate the I-V characteristics of the panel under different temperature conditions:





About the Virtual Instrumentation and Renewable Energy Laboratory - Transilvania University

Laboratory members:

            Dr. Petru Adrian COTFAS

            Dr. Daniel Tudor COTFAS


The lab is integrated in the Electronics and Computers Department, Electronics and Computers Science Faculty, Transilvania University of Brasov. Transilvania University of Brasov was founded in 1948 and has now 18 faculties, offering bachelor, master and doctoral studies to over 22000 students. Advanced research is developed in 22 centers focusing on major topics of sustainable development: Renewable Energy Systems, novel Energy Efficiency in processes, advanced solutions for Energy Saving products and processes, Natural Resources preservation and use, Health and Life Quality, and Education, Culture, Communication and Economic Development.


There are many educational and industrial applications using the NI products at the University:


  • Simulation of Physics labs using the graphical programming language LabVIEW 
  • SolarLab – educational and research system powered by NI LabVIEW and NI ELVIS II platform




  • RELab (Renewable Energy Laboratory) – educational and research system powered by NI LabVIEW and NI ELVIS II and myDAQ platforms


  • STNV 25120469 – research contract for development of drivers LabVIEW Ecochemie - Netherlands
  • Weighing and monitoring system of Mass Distribution for S.C. IAR S.A. Brasov, Romania
  • Management system for the utilities implemented at S.C. IAR S.A. Brasov, Romania


The ReLab system is a very good solution for the study of the renewable energy. The design of the entire RELab circuit was done using the NI Multism and NI Ultiboard. The RELab system was recognized as a break-through tool in education and won three awards at international competitions organized by National Instruments:

  • Graphical System Design Achievement Awards - Education category - August 2013
  • Graphical System Design Achievement Awards - Editors Choice Award - August 2013
  • Graphical System Design Achievement Awards - NI Community’s Choice - August 2013.




  1. 1.   D. T. Cotfas, P. A. Cotfas, S. Kaplanis: Methods to determine the dc parameters of solar cells: A critical review, Renewable and Sustainable Energy Reviews, vol. 28, 2013, pp. 588–596.
  2. 2.
  3. 3.   D. Sera, R. Teodorescu, PV panel model based on datasheet values, Industrial Electronics, 2007. ISIE 2007. IEEE International Symposium on, pp. 2392 – 2396, 2007

How to Share Content ...

This community has been created to help engineers, designers and students to collaborate freely on the internet, at a single location. Content that can be shared are reference designs, example circuits, and custom component symbols and landpatterns. To share content:


  1. Create your design with any custom design elements
  2. Select File > Save
  3. Save the file with the notation Design_Application_UserName.ms10 (e.g.Hardware_Connector_Jane.ms10)
  4. In the Collaborate section of the Circuit Design Community click on Create a Document
  5. Enter a Title with the notation, Manufacuturer_Device
  6. Enter a Description
  7. Click on Choose File to upload the schematic
  8. Enter Tags such as Multisim Reference Design
  9. Click on the Publish button


Please adhere to any copyright policy placed upon content being shared.

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