Proteus

Proteus by Labcenter Electronics blends schematic capture, PCB layout, and powerful circuit simulation (including microcontroller co-simulation). Engineers can test designs with virtual components (MCUs, sensors, etc.) before physically building prototypes. The software supports advanced features like high-speed design, differential pair routing, and 3D board visualization. An extensive library covers common ICs, plus developers can create custom parts. Proteus suits educational use, hobby projects, and professional environments requiring thorough simulation of embedded systems. Though commercial licenses cost money, it remains popular for interactive circuit testing.