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Overview
The Electronics Workbench SPICE Simulation Fundamentals series is your free resource on the internet for learning about circuit simulation. The series is a set of tutorials and information on SPICE simulation, OrCAD pSPICE compatibility, SPICE modeling, and other concepts in circuit simulation.
For more information, see the SPICE Simulation Fundamentals main page.
The series is divided among a number of in-depth detailed articles that will give you HOWTO information on the important concepts and details of SPICE simulation.
Circuit simulation is an important part of any design process. By simulating your circuits, you can detect errors early in the process, and avoid costly and time consuming prototype reworking. You can also easily swap components to evaluate designs with varying bills of materials (BOMs).
What are SPICE Simulation Options?
SPICE simulation can help to predict the behaviour of electronic circuits of almost any complexity. The SPICE simulator will execute a desired transient, DC, AC or other simulation based on the parameters of the simulation (e.g. length of time, start/stop frequencies, initial conditions, etc.) and based on the options chosen. The SPICE options set will affect simulations in various ways.
A Tradeoff Between Speed and Accuracy
Although the SPICE models used in a SPICE simulation can greatly affect the accuracy of the results, simulation settings also contribute to varying degrees of accuracy. SPICE simulation options generally allow the user to gain more accuracy in the results at the cost of the speed of the simulation.
To understand the tradeoff between speed and accuracy in SPICE simulation one must consider a number of factors. SPICE simulation was created over 30 years go and around that time a typical computer had less power than the average microwave oven did thirty years later. Computing power was very expensive. The simulation of a circuit to the highest degree of accuracy could have taken longer and cost more money than building the actual circuit to see the results. Also, consider that the broad purpose of circuit simulation is to augment basic hand calculations and predict general circuit behavior. With these considerations in mind, the designers of SPICE created a program that could produce reasonably accurate results in a cost-effective manner. They also included many options to allow engineers to customize the accuracy of a simulation.
As computing power has increased exponentially over the years, so have the complexity of circuit designs being simulated. Speed and accuracy are still important factors to consider when simulating circuits.
Changing SPICE Simulation Options
In Multisim, you can change the SPICE options for interactive simulation by clicking Simulation >> Interactive Simulation Settings from the main menu. You can change settings for individual simulations by navigating to the Analysis Options tab for each desired simulation and clicking "Use Custom Settings".
A Listing of SPICE Simulation Options
SPICE2 Emulation Mode
In addition, the following options have the listed effect when operating in SPICE2 emulation mode:
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Legal
This tutorial (this "tutorial") was developed by National Instruments ("NI"). Although technical support of this tutorial may be made available by National Instruments, the content in this tutorial may not be completely tested and verified, and NI does not guarantee its quality in any way or that NI will continue to support this content with each new revision of related products and drivers. THIS TUTORIAL IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND AND SUBJECT TO CERTAIN RESTRICTIONS AS MORE SPECIFICALLY SET FORTH IN NI.COM'S TERMS OF USE (http://ni.com/legal/termsofuse/unitedstates/us/).