Here are some Circuit Diagram Drawing Tools for Android Tablets, they may be still under development. It may be Interesting to explore and try out.
Schematic Demo is an easy-to-handle and comfortable CAD-software, developed for different kinds of diagrams.
Schematic Demo Dmitry Ustimov
Editing objects performed by interaction with a device touch screen. You can create and edit such graphic objects as: - Point, Line, Polyline, Bezier curve, Arc, Ellipse and Rectangle.
Electronic schematic drawing application for Android by Harry Konstas
palmDraft lite ElectronicsCAD
This is a bitmap-based CAD, featuring a high definition, flick-panning, pinch-zoom-able working canvas optimized for finger and pen drawing. It's as easy to manipulate as a sheet of paper. The schematics file format is standard .PNG bitmap file format which can be easily exported and shared for printing.
The MCU simulator for Android OS runs Assembly language code similar to the 68705 MCU on a simulated on-screen prototype board. Great for embedded applications hobbyists, students, teachers or anyone who likes to experiment with electronic Micro-controller prototype boards. It's fun for learning assembly language too!