Zen Circuit Lab vs Diode (withdiode.com)
If you came looking for Diode: Zen Circuit Lab is a free browser simulator with a breadboard, a 3D view and an Arduino, and a great deal more around them. Its users said Diode was beautiful but clunky to build in; the lab keeps the 2D bench for building and the 3D view for looking.
Facts about Diode (withdiode.com) are from its public pages and documentation at the time of writing; tell us if something is out of date. Nothing here is a ranking: the two tools are for different jobs.
Side by side
| Zen Circuit Lab | Diode (withdiode.com) | |
|---|---|---|
| Price | Free, no account needed (an account only keeps progress across devices) | Was free; the site has been offline since early 2026 and its creator announced it was shut down |
| Runs on | Browser, desktop or laptop; lessons work on a phone | Browser (WebGL) |
| Simulation | Electrical solver (modified nodal analysis) for analog and digital: every voltage and current, parts that heat, trip and burn | Simulation of basic circuits with smoke on a shorted battery |
| View | 2D bench with a schematic view; 3D view of the bench, breadboard and perfboard | A 3D breadboard with flexing wires, the feature that made it famous |
| Breadboard | Yes | Yes |
| Parts | 293 parts modelled on real products, each with a datasheet card | A small library: resistors, capacitors, LEDs, transistors, a 555, switches, motors |
| Microcontrollers | ESP32 (WROOM, S3), Arduino Uno and Nano, Raspberry Pi Pico 2, LILYGO T-SIM: Arduino C++ sketches run by the lab's own compiler (not cycle-accurate firmware) | Arduino Uno, with real AVR emulation |
| Analog solver | Yes | Partly |
| Solar | Panels, PWM and MPPT controllers modelled on EPEVER, Renogy and Victron, inverters | No |
| Batteries and BMS | Cells and packs with real capacity and curves; BMS boards modelled on real products | No |
| Instruments | Multimeter, clamp meter, oscilloscope, function generator, LCR meter, electronic load, logic analyser | Voltage probing |
| Perfboard and PCB | Perfboard and PCB layout and routing, run on the same solver | No |
| House wiring | House wiring with breakers, RCD, outlets, appliances | No |
| Learning | 193 lessons, 7 courses, 66 guided builds with test sheets | An Explore page of community projects |
| Sharing and import | Share links; import Falstad, Wokwi and SPICE; export SPICE | Share links |
| Source | Not open source | The creator said he would likely open-source it |
Where Diode (withdiode.com) is better
- The 3D breadboard looked like a photograph, and the wires flexed. It is the reason it went viral.
Where Zen Circuit Lab is better
- It still works, and it is free with no account.
- 290 parts, power systems, instruments, courses, perfboard and PCB, where Diode had a dozen parts and an Uno.
- A 3D view of the bench and the breadboard, with parts you can drag in 3D, and a 2D bench for building quickly, which is where Diode's users said the 3D got in the way.
Open Zen Circuit LabFree, in your browser, no account needed.