iCircuit 1.4.6 for iOS was released today featuring improved circuit simulator code to speed it up on modern hardware and a bunch of bug fixes.
This is a compatibility upgrade to make sure it works well on iOS 6 and the iPhone 5. New features will be coming in v 1.5, but I wanted to make sure this version got out before then.
Update There was a bug introduced in this version that causes "Singular Matrix" errors to be displayed on iOS 4.3 devices. This bug has been fixed and new version (1.4.7) was sent to Apple on Friday, Sep 21. I am very sorry for this mistake and appreaciate your patience while we wait for approval.