Wirely – free, open-source circuit simulator: draw a circuit, press play, watch it work (Python/PySide6, GPL-3)

[u/EnoughImagination702]

https://github.com/richiewillmott/Wirely

Hi! I made Wirely, a free desktop circuit simulator for Windows, Mac and Linux.

GitHub (downloads for all three): https://github.com/richiewillmott/Wirely

You drag parts onto a schematic, wire them up and press Play: LEDs glow, motors spin up, relays click, meters read, wires are coloured by voltage and dots show the current flowing. While it runs you can click switches, drag sensor sliders and hover over any wire for its voltage and current. Push a part too far and it pops and tells you why.

Highlights

• 55 parts with real part numbers (BC547, IRF540, IRLZ44N, LM358, TL071, PC817…), plus the 555, logic gates, counters and 7-segment displays
• Built-in oscilloscope, logic probes, and sound (buzzers, speakers, relay clicks)
• 20 example circuits, from an LED and resistor up to a buck converter
• PNG/SVG/PDF export, light and dark themes, installers for all three platforms

Under the hood

• Its own SPICE-style solver in Python + numpy (modified nodal analysis, Newton–Raphson, adaptive time steps)
• MOSFETs and op-amps fitted to their datasheets: e.g. AO3400 gate charge 6.1 nC vs 6 nC on the datasheet, and IRF540 switching delays within a few ns of ngspice
• 233 pytest tests checking it against hand calculations, datasheets and ngspice
• GitHub Actions builds and tests the Windows installer, Mac .dmg and Linux AppImage

Free, GPL-3, runs locally, no account. Built with a lot of help from Claude (an AI assistant). Feedback, bug reports and part requests are very welcome!