Circuit Simulation - An Introduction

Elecronic circuit is a complex mix of devices such as sources and components in which terminals are connected together by conducting wires or tracks.The best method to test an electronic circuit design is to use a circuit simulator and make a simple model of it to observe how it works.Simulator is a system that simulates an environment for the purpose of training or research.Simulation of an electronics circuit before actually fabricating it not only enhance the performance and efficiency,but also provides a deep insight into the behaviour of the electronics design.In principle,electronic circuit simulators use mathematical models to replicate the behaviour of a real electronic circuit.

Simulators can mimic exceptional conditions (or characteristics) of a real processing and serve various purposes,starting from training to testing.There are various software tools available to simulate electronic circuits.Circuit simulators can be relegated into two main classes,viz, Analogue and Digital.Here is a brief guide focused on electronic circuit simulation softwares,many of which are available free over the internet.

• Qucs: This open-source software Qucs (Quite universal circuit simulator) aims to support all kind of circuit simulations.Microsoft Windows,different Linux OS and Mac OS are supported platforms.
• Simulo v 2.5: This easy to use simulation software is designed for students and hobbyists.Simulo digital simulator includes many digital items and can simulate circuit operation.Simulo supports Microsoft Windows platform and can be run from Windows XP to Windows 7.
• Electric 8.11: Electric 8.11 is another flexible and powerful open-source electronic design automation (EDA),which can handle many forms of design and simulation.Supported OS platforms are Microsoft Windows,Mac and Linux.

Logisim and Karnaugh Map: A digital logic circuit simulator can check the logic correctness of any hardware design.Logisim is an easy to handle digital logic circuit simulator that can be used for basic to advanced level logical testing.Further,this simulator allows printout of the designed circuit.Logisim is an educational software that was built for students and distributed under GPL license.Another software in this class is the open-source simulator Karnaugh Map,specially designed for educational purpose.Simplified Boolean expression is just a click away when using this simulator.Karnaugh Map supports both Microsoft Windows and Linux platforms.

Although circuit simulator is infact a designer's tool,it can also be used in training and education as stated earlier.Instead of getting hands-on experience of elecctronic circuits on the worktbench (real world),the student or hobbyist can a similar experience by putting hands on computer keyborad (virtual world).Circuit simulation using software offers many advantages including:

• Precision timing of events.
• Speed in circuit assembly,testing and modification.
• Equivalent of an unlimited range of precision test instruments and tremendous range of components.

Various commercial simulation softwares nearly all have the same basis,but differ in the details of circuit entry,analysis and display.There are ofcourse,some pitfalls to be avoided when selecting and using a simulator software.For instance,with a Demo version,or a student/entry level edition,user can only enter and analyse circuits of very limited size.