Logisim - Logisim is an educational tool for designing and simulating digital logic circuits.
LTspice - LTspice® is a high performance SPICE simulation software, schematic capture and waveform viewer with enhancements and models for easing the simulation of analog circuits.
Hradla - Logical Network Editor that runs in your browser.
Circuit Tree - Design and order Boards in Minutes
Digital - A simulator for digital circuits.
Circuit Simulator - Animated electronic circuit simulator using ideal components to visualize voltage and current.