proteus VSM is described as 'A virtual simulation environment for electronic circuits with support of digital and analog devices. It also provides virtual instruments and virtual debugging tools' and is a Circuit Simulator in the Education & Reference category. There are more than 10 alternatives to proteus VSM for a variety of platforms, including Linux, Windows, Mac, Online / Web-based and Chrome OS. The best alternative is Circuit JS, which is both free and Open Source. Other great apps like proteus VSM are Autodesk Tinkercad (Free Personal), QUCS (Free, Open Source), Autodesk EAGLE (Free Personal) and Xcos (Free, Open Source).
Tinkercad is a super easy-to-use, browser based 3D design tool. With Tinkercad you can create 3D printable items: toys to play with, decoration to light up your home or jewelry to express yourself. You dream it, you can make it!
The Quite Universal Circuit Simulator (QUCS) is an integrated circuit simulator allowing the simulation and graphical presentation of results of large-signal, small-signal and noise behavior in circuits.
SimulIDE is a simple real time electronic circuit simulator. It's intended for general purpose electronics and microcontroller simulation, supporting PIC and AVR. PIC simulation is provided by gpsim and avr simulation by simavr.
KTechLab is an IDE for microcontrollers and electronics. It supports circuit simulation, program development for microcontrollers and simulating the programmed microcontroller together with its application circuit.
MyOpenLab is a platform for finished elements (program components) that can be linked together. You can also MyOpenLab with a house builder compare the building blocks used to build his house. The modules often create others.
It is a circuit simulator on a virtual breadboard. it supports virtual components like microcontrollers, TTL, graphical and alphanumerical LCDs and others in addition to virtual instruments and certainly the basic components (resistors, capacitors..).