Like ngspice, but visual, in your browser, and built for digital logic
ngspice is the open source SPICE simulator for electric and electronic circuits. It is SPICE compatible and reads PSpice, LTspice and HSpice model libraries, simulates transistors, diodes, passive parts and transmission lines, and also handles digital circuits (event driven) and mixed-signal designs. It has no schematic entry of its own: its input is command line or file based, it builds on Windows, Linux, FreeBSD and macOS, and other tools use it as their engine, including KiCad. If that is what brought you here, digiwleea is a free, in-browser alternative with a different angle: you build a computer from the transistor up.
What ngspice is good at
It is free, open and accurate, which is why it sits inside other design tools, and for anyone who wants real analog behavior from a netlist (bias points, transients, frequency response) it is a serious, scriptable simulator. (digiwleea is an independent project, not affiliated with ngspice.)
How digiwleea is different
digiwleea is not a SPICE simulator and has no netlist files: you place transistors and wires on a canvas in your browser and the simulator treats each transistor as a switch, which is the level you need for digital logic and computers. From there a guided 40+ level course takes you through gates, adders, latches, registers and RAM to an 8-bit CPU that you program in assembly, with an AI tutor (Wleea). ngspice is the better pick for analog and mixed-signal accuracy; digiwleea is the better pick for learning digital logic and computer architecture visually. Other SPICE tools compared: LTspice, PSpice and Qucs.
| ngspice | digiwleea | |
|---|---|---|
| Simulation | SPICE: analog, digital and mixed-signal | Switch-level digital logic |
| Input | Netlist files or the command line | Drag-and-wire circuits in the browser |
| Runs on | Windows, Linux, FreeBSD, macOS (or inside other tools) | Any modern browser, nothing to install |
| Price | Free, open source | Free lab and Act I; Premium for the full course |
| Guided course to a CPU | No | Yes, 40+ levels |
No sign-up is needed to start: open the lab and place your first transistor, or read the free theory course. The account (and the AI tutor) are optional.
See for yourself: build a logic gate from transistors in the simulator, then follow the path from sand to an 8-bit CPU.
Open the digiwleea lab →Frequently asked
Is digiwleea a good ngspice alternative?
Yes, if you want to understand digital logic from the ground up. digiwleea is a free, in-browser simulator with a guided 40+ level course where you build every gate from CMOS transistors and work up to a real 8-bit CPU, with an AI tutor to help.
Is digiwleea free?
The sandbox lab and the first act of the course are free and need no sign-up. An optional account adds the AI tutor and cross-device sync; the full course and expanded AI tutoring are included in the monthly or annual Premium subscription.
Do I need to install anything?
No. digiwleea runs entirely in your browser, on desktop or mobile, and works offline once loaded.