In short you must have the simulation models of the components in order to imitate their actual behavior.If you have the component in your circuit whose simulation model is not present in the library of your software then the software will be unable to simulate the behavior of the circuit.While simulating any circuit it is important to keep in mind that the simulation models of all the components that are being used in your circuit or embedded system must be present in the library of the software.There are a lot of the software and online tools available for simulating the circuit or embedded systems, among them Proteus holds the significant position which is equally popular among students and professionals. The simulation software calculates the behavior of the circuit by calculating the mathematical equation of all the components.Let us now summarize all the custom made simulation models required for simulating the embedded system designed based on the Arduino microcontrollerdevelopment board.In this projectiot123 tutorial we will Learn the Download Proteus Library of Components.The simulation model of an electronic component contains the information about the input and output relationship of the electronic component in the form of the mathematical equation.