CirSpice

Your .CIR schematics, simulated on your Mac.

CirSpice is a Mac app that opens Micro-Cap .CIR files, shows the schematic and simulates it with ngspice. It works entirely on your Mac: no account, nothing uploaded.

Coming to the Mac App Store

CirSpice is in beta testing. It is not yet available to download.

Opens
Micro-Cap .CIR schematic files
Simulator
ngspice 45.2
Analyses
Transient, AC, DC, operating point
Requires
Mac with Apple silicon, macOS 14 or later
Your files
Stay on your Mac
Price
Free to open and view. One purchase to edit and simulate.
The CirSpice window: the schematic of an inverting amplifier above, and below it the plot of its transient run, input step and output.

From the file to the waveform

Open the schematic

Your .CIR file opens as the schematic you drew, with its parts, wires, labels and analysis settings.

Know before you run

CirSpice tells you whether a file is ready to simulate. If it is not, it names the part or analysis that is in the way.

Run and measure

Run transient, AC, DC and operating point analyses. Probe the schematic, add measurements, and export plots as PNG, SVG or CSV.

Simulation by ngspice

CirSpice simulates with ngspice 45.2, the widely used open source SPICE simulator, running right on your Mac.

Nothing is hidden: View > Show Netlist shows exactly what was simulated.

ngspice is a different simulator from the one in Micro-Cap, so results can differ. Check anything critical before you rely on it.

An AC analysis in CirSpice: gain in decibels and phase in degrees against frequency, from 1 Hz to 1 MHz.

Edit, rerun, save

Place parts, draw wires, change values and analysis limits, then run again. Step a value and see every run on one plot. Check tolerances with Monte Carlo and worst case analyses.

A file you save is still a .CIR file. CirSpice keeps its own settings in a separate file beside it and adds nothing to your circuit.

The Transient Analysis Limits panel open beside a schematic and its plot.

Nothing leaves your Mac

Your circuits are your work. CirSpice works entirely on your Mac and never connects to the internet.

  • No account and no sign-in.
  • Your files are never uploaded.
  • No analytics and no tracking, in the app or on this site.
  • Purchases are handled by Apple, through the Mac App Store.

Read the privacy policy

Free to open, one purchase to work

Free

Open files, view the schematic, see whether it is ready to run, and export. No time limit.

14-day trial

Everything, for 14 days. The trial starts when you choose, not when you install.

CirSpice Standard

One purchase unlocks editing, saving and simulation. No subscription. The price is shown on the Mac App Store.

Good to know

  • Not every .CIR file opens or runs yet. When one does not, CirSpice tells you which part or analysis is the reason.
  • CirSpice is not Micro-Cap and does not include it. Micro-Cap is a product of Spectrum Software. CirSpice is not affiliated with or endorsed by Spectrum Software.
  • Results come from ngspice and can differ from another simulator's results for the same circuit.
  • CirSpice is for the Mac.

Questions before you try it? Write to support@cirspice.com or read Support.