
circuits.io
VoltSim
Diode
Circuit Stickers
PhET Interactive Simulations
CodeBlinks
circuits.ioVoltSim - VoltSim is an interactive realtime circuit simulator. It has digital and analog components and even Integrated Circuits. It is the perfect companion to students, hobbyists, and engineers.
Diode - diode - Android app to interact with reddit.
Circuit Stickers - Peel-and-stick electronics for crafting circuits.
PhET Interactive Simulations - Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations.