This paper presents a system for recognizing sketched logic circuits in real-time and graphically simulating them afterwords. It has been developed for use in university and school education. Circuit gate symbols are recognized using a multilayer perceptron network. The simulation is fully controlled by hand-drawings, and the inputs to circuits can be defined by writing numbers next to them. In addition to the simulation of simple circuits, recursive circuits can also be handled by the system. Furthermore, clock elements can be added for the purpose of synchronization, and circuits can be stored to be reused as sub-circuits, allowing the user to build arbitrary complex configurations. The usability of the system has been tested in a small video-taped laboratory test.