Altium Designer might be a bit more popular than iCircuit. We know about 1 link to it since March 2021 and only 1 link to iCircuit. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
For a nice, polished, non-skeuomorphic circuit simulator, see iCircuit [1], which provides native MacOS and iOS clients (based on the Falstad JS circuit simulator mentioned elsewhere in this thread, if I recall correctly). It differs from most SPICE-based simulators in that there is no edit or run mode - the circuit is always simulating in transient mode so updates happen in real time. [1]... - Source: Hacker News / over 1 year ago
Check out Altium’s website (altium.com. A lot of free resources that might help. They also have a YouTube channel. Good luck. Source: about 1 year ago
Circuit Simulator - Animated electronic circuit simulator using ideal components to visualize voltage and current.
KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
Virtual Breadboard - It is a circuit simulator on a virtual breadboard.
Autodesk EAGLE - Autodesk EAGLE is an electronic design automation (EDA) software.
OpenModelica - OpenModelica – A Free Modelica Environment!
EasyEDA - EasyEDA - Web-based EDA suite; runs in browser.