Design analog circuits. Check the results.
Start from an example, describe your circuit, or bring a SPICE netlist. Inspect the schematic, measure cutoff and gain against your targets, and continue editing in KiCad.
Built-in examples use no AI credits. No installation required.
How it works
Describe
Start with an example or describe a filter or gain stage. Include the signal, supply, load, and result you need.
Simulate
Run ngspice in your browser. Inspect waveforms and compare supported cutoff and gain targets with measured AC results.
Iterate
Ask for a change, inspect the updated circuit, and rerun its checks. Review assumptions and any targets the simulation cannot verify.
Export
Export to KiCad for PCB layout or grab the raw SPICE netlist and keep moving.
Why Circ AI?
Keep the circuit, its requirements, and the simulation results together as you work through a design.
No setup, no install
Open a built-in example or bring a SPICE netlist. Explore the circuit and its waveforms in a browser workspace.
Design through dialogue
Ask “increase the gain by 6dB” or “add a bypass capacitor.” Inspect the suggested changes and their simulation results.
Measured target checks
Save cutoff and gain targets with tolerances. See whether the matching AC run meets them, misses them, or cannot verify them. Model assumptions remain part of the result.
Export to KiCad
Export an editable KiCad schematic for further design work, or download a PDF with the saved requirements, checks, and simulation source.
Simple pricing
Start free. Upgrade when you need more.
Top-up
$7.99 once
No subscription
Pro members pay just $5
- 12 circuit designs & revisions (no expiry)
- 10 saved circuits
- KiCad export
Pro
$19.99/mo
Billed monthly
or $12.42/mo billed annually
- 60 circuit designs & revisions/month
- Unlimited saved circuits
- KiCad export
Pro Annual
$149/yr
Just $12.42/mo — save $91/yr
- 60 circuit designs & revisions/month
- Unlimited saved circuits
- KiCad export
FAQ
- What counts as a “design & revision”?
- AI-assisted designs and revisions use your allowance. Opening an initial built-in example uses no AI credits; asking the AI to change it uses your normal allowance.
- What simulator do you use?
- We run ngspice for transient (.tran), AC frequency (.ac), and DC sweep (.dc) analysis. Saved cutoff and gain targets can be checked against AC results. Other behavior needs review of the simulation and model assumptions.
- Can I import my own SPICE netlist?
- Yes. You can paste a SPICE netlist directly or drag and drop a .cir/.spice file. The AI can then help you modify and iterate on it.
- What components are supported?
- Resistors, capacitors, inductors, diodes, BJTs, MOSFETs, JFETs, op-amps (with realistic GBW models), voltage/current sources, and common ICs like the 555 timer and LM386.
- Is my circuit data private?
- Yes. Your circuits are stored in your account and are not shared or used for training. You can delete them at any time.
- Can I cancel my subscription?
- Yes, anytime. Your saved circuits remain accessible on the free tier after cancellation.
What will you build?
Describe it. Simulate it. Export it.
Try it free →