Micro-Cap alternative: digital logic in your browser
Micro-Cap is a circuit simulator from Spectrum Software, a company founded in 1980 whose first product was a logic designer and simulator for the Apple II. Its site describes Micro-Cap 12 as analog, mixed-mode and digital simulation software, SPICE and PSpice compatible, and Micro-Cap 10, 11 and 12 are now free downloads that need no key. The latest listed build, 12.2.0.5, is dated June 17, 2021, and it installs on Windows from a setup program, with libraries, sample circuits and the user's and reference guides included. If you came looking for a free simulator to learn digital logic, digiwleea is a browser-based alternative with a narrower, deeper focus.
What Micro-Cap is good at
It is a full SPICE-class simulator, now at no cost: analog circuits with real device models, digital logic, and mixed circuits where both meet, with the manuals and sample circuits of a commercial product. For transistor-level analog work, timing and waveforms in volts, it does far more than a logic simulator can. (digiwleea is an independent project, not affiliated with Spectrum Software.)
How digiwleea is different
digiwleea simulates digital logic only, at the switch level: every wire is 0, 1 or floating, with no voltages, currents or device models. In exchange it is built for learning: it runs in any modern browser with nothing to install, you build NOT and NAND from CMOS transistors and work up to adders, latches, registers, RAM and an 8-bit CPU that runs a stored program, plus the assembly language behind it, through a 40+ level course where every part is checked against its truth table, with an AI tutor (Wleea). For analog circuits, Micro-Cap, LTspice or ngspice is the better tool.
| Micro-Cap | digiwleea | |
|---|---|---|
| Runs on | Windows (setup program) | Any modern browser, Chromebooks and phones included |
| Simulates | Analog, mixed-mode and digital circuits (SPICE and PSpice compatible) | Digital logic at the switch level: 0, 1 and floating |
| Latest version | 12.2.0.5, dated June 17, 2021 | Updated continuously |
| Learning path | User's and reference guides, sample circuits | A 40+ level course from transistor to CPU, with an AI tutor |
| Price | Free (versions 10 to 12, no key) | Free lab and Act I; Premium for the full course |
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.
More comparisons: Electronics and SPICE simulators
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 Micro-Cap free?
Yes. Spectrum Software's download page says Micro-Cap 10, 11 and 12 are now free and require no key. Older versions (5 to 9) still need a key.
What is the latest version of Micro-Cap?
The download page lists Micro-Cap 12, version 12.2.0.5, dated June 17, 2021, as a full CD image or an executable-only update.
Does Micro-Cap run on Mac or Linux?
It installs on Windows from a setup program. digiwleea runs in any browser, so it works on Mac, Linux, Chromebooks and phones for digital logic.
Is there an online alternative to Micro-Cap?
For digital logic, digiwleea runs in the browser with a free lab and first course act. For analog circuits online, Falstad's circuit simulator is free in the browser.