The AI-Powered
Circuit Simulator
Built for the Future.
Design, simulate, and optimise analog & digital circuits in your browser — with an intelligent AI co-pilot and agentic simulation engine. Free. Forever. No install.
No credit card · No account · Works in any browser
Circuit IntelliSim Usage Statistics
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Traditional Circuit Simulators Were Not Built for the AI Era.
Electronic engineers and students have relied on desktop SPICE simulators and basic browser tools for decades. These tools are powerful but isolated — they require manual parameter tuning, offer no intelligent assistance, and produce errors that novices cannot easily diagnose. The circuit simulation landscape has remained fundamentally unchanged since the 1980s, while every other engineering discipline has embraced artificial intelligence and cloud-based collaboration.
The result: hours wasted debugging circuits that a trained engineer could fix in minutes. Learning curves that discourage students from exploring electronics. Prototyping cycles that add days to hardware timelines. Research teams stuck in silos, unable to share or iterate on designs efficiently. For startups building hardware products, these delays translate directly into lost revenue and missed market windows.
Circuit IntelliSim was engineered to solve this — not by iterating on old tools, but by reinventing circuit simulation from the ground up with AI and agentic intelligence at the core. It represents a paradigm shift in how engineers interact with electronic design automation, bringing the power of large language models and autonomous agents directly into the schematic editor.
No Intelligent Assistance
You diagnose every error manually with no AI to catch mistakes or suggest fixes. Every fault requires deep domain expertise to identify and resolve.
Steep Learning Curve
Mastering SPICE syntax takes months, alienating students and beginners who want to focus on circuit concepts rather than tool commands.
Desktop-Locked Software
Installing and licensing EDA tools is slow, expensive, and institution-dependent. You cannot work from any device or collaborate in real time.
Zero Automation
Every simulation parameter must be tweaked manually, iteration after iteration, with no autonomous optimisation or parameter sweep capability.
A Next-Generation AI Circuit Simulator. Built for Engineers Who Think Ahead.
Circuit IntelliSim is a free, browser-based circuit design and simulation platform that integrates a powerful AI co-pilot directly into your workflow. Whether you are sketching an RC filter or designing a multi-stage analog amplifier, Circuit IntelliSim understands your intent, suggests optimisations, and can simulate design variations autonomously. It is the most advanced online circuit simulator available today, combining the precision of SPICE with the intelligence of modern AI.
Unlike conventional simulators that demand manual expertise at every step, Circuit IntelliSim's agentic AI engine can receive a high-level specification in plain English — and produce a working, simulated schematic in seconds. Whether you are a student learning Kirchhoff's laws or a professional engineer validating a power supply design, Circuit IntelliSim accelerates your workflow by an order of magnitude.
- ✅Drag-and-drop schematic editor with 500+ components
- ✅SPICE-accurate simulation: analog, digital, and mixed-mode
- ✅AI co-pilot providing real-time, context-aware design suggestions
Everything You Need to Design and Simulate Circuits — Intelligently.
Intuitive Schematic Editor
Drag-and-drop 500+ elements with smart auto-connect and human-readable value formatting. The editor is designed for speed, with keyboard shortcuts, snap-to-grid, and component search that makes circuit entry effortless.
High-Fidelity SPICE Simulation
Time-domain, frequency-domain, and DC analyses with a precision numerical solver. Results render in seconds with interactive, zoomable waveform plots and measurement cursors.
AI Circuit Co-Pilot
Describe a circuit in plain English and the AI generates a working schematic. Get real-time error explanations, component value recommendations, and design optimisation suggestions as you work.
Agentic Simulation Engine
Set a design goal — the AI agent iterates autonomously, testing and adjusting component values and topologies until it delivers an optimised circuit that meets your specifications.
Intelligent Fault Diagnosis
When simulation fails, the AI diagnoses the root cause, explains it in plain language, and recommends the fix — saving hours of manual debugging and frustration.
Multi-Format Export
Export schematics as PDF, SVG, PNG, or EPS for presentations, reports, and publications. Share circuits via unique, shareable URLs with collaborators anywhere in the world.
Analog & Digital Mixed-Mode
Simulate analog and digital components side-by-side in a single circuit. Combine operational amplifiers with logic gates, ADCs with microcontrollers, all in one unified simulation.
Natural Language Prompting
Type "design a 555 timer astable oscillator at 1kHz" — IntelliSim builds, wires, and simulates it instantly. Over 200 circuit typologies are supported out of the box.
No Install. Always Accessible.
Lives in your browser. Any device. Any OS. Chrome, Firefox, Safari, Edge all supported. Access your circuits from a laptop, tablet, or even a mobile phone, anywhere in the world.
The World's First Agentic AI Circuit Simulator.
Circuit IntelliSim doesn't just assist — it acts. Our agentic AI receives a goal, plans a strategy, executes simulations, evaluates results, and iterates — fully autonomously.
AI Co-Pilot — Your Expert Engineering Partner, Always On
The AI co-pilot lives alongside your schematic editor. As you draw, it analyses topology in real time, identifies issues (incorrect biasing, unstable feedback, impedance mismatches), and surfaces recommendations — like a senior engineer looking over your shoulder. It understands the context of your entire design, not just individual components, enabling holistic circuit analysis that catches issues traditional tools miss entirely.
- ✓ Context-aware component suggestions
- ✓ Real-time simulation error explanations
- ✓ Natural language Q&A about your circuit
- ✓ Auto-complete for component values
The agentic loop runs autonomously until your design goal is met.
Agentic Simulation — Set a Goal. Let AI Do the Rest.
Tell IntelliSim your target — "Design a 5V to 3.3V buck converter with >90% efficiency" — and the agentic engine proposes topologies, selects components, runs simulations, evaluates metrics, adjusts parameters, and returns a verified, optimised design. No manual iteration required. The agent handles backtracking, convergence detection, and multi-variable parameter sweeps entirely on its own.
- ✓ Goal-directed autonomous design
- ✓ Multi-variable parameter sweeping
- ✓ Convergence detection and backtracking
- ✓ Design report generation
Generate Circuits From Plain English
No schematic editor experience? No problem. Type "Create a low-pass Butterworth filter with a 3kHz cutoff" and IntelliSim's generative AI produces a correctly wired schematic, runs the simulation, and shows the frequency response — in under 10 seconds. This capability makes circuit design accessible to students, hobbyists, and anyone who can describe what they need in natural language.
- ✓ 200+ supported circuit typologies
- ✓ Instant schematic generation
- ✓ Editable output — refine as needed
- ✓ Plain-English explanation mode for students
Type your circuit description:
"Design a 555 timer astable oscillator at 1kHz with 50% duty cycle"
See Circuit IntelliSim in Action.
No sign-up. No tutorial. Just click and start simulating.
Live preview · Open in full screen →
Built for Every Kind of Circuit Designer.
Learn Electronics With an AI Mentor
Circuit IntelliSim transforms how engineering students learn circuit design. Instead of struggling with cryptic SPICE error messages, students get plain-English explanations of what went wrong and how to fix it. The AI co-pilot acts as a patient, always-available tutor that can explain concepts from Ohm's law to Bode plots in the context of the student's own circuit.
Whether you are working on lab assignments, preparing for exams, building final year projects, or simply exploring electronics as a passion, Circuit IntelliSim gives you access to professional-grade simulation tools without the steep learning curve or expensive software licences that traditionally gatekeep this technology.
- ✓ Complete lab assignments faster with AI guidance
- ✓ Exam preparation with interactive circuit exploration
- ✓ Build impressive final year projects with autonomous simulation
- ✓ Interactive concept learning with plain-English explanations
Circuit IntelliSim vs. Traditional Circuit Simulators.
See how we compare across the features that matter most to engineers, students, and educators.
| Feature | Circuit IntelliSim | Typical Browser Tools | Desktop SPICE |
|---|---|---|---|
| AI Co-Pilot | ✅ Full integration | ❌ None | ❌ None |
| Agentic Simulation | ✅ Autonomous AI agent | ❌ None | ❌ None |
| Natural Language Input | ✅ Generate from text | ❌ None | ❌ None |
| AI Fault Diagnosis | ✅ Instant | ❌ Manual only | ❌ Manual only |
| Browser-Based | ✅ No install | ✅ Yes | ❌ Install required |
| Free to Use | ✅ Completely free | ⚠️ Limited free tier | ❌ Expensive licence |
| Sign-Up Required | ✅ None | ⚠️ Usually yes | ❌ Licence required |
| Analog Simulation | ✅ Full SPICE | ⚠️ Basic | ✅ Advanced |
| Digital Simulation | ✅ Mixed-mode | ⚠️ Limited | ✅ Advanced |
| Export Quality | ✅ PDF/SVG/PNG | ⚠️ Basic PNG | ✅ Professional |
| Mobile-Friendly | ✅ Fully responsive | ⚠️ Partial | ❌ No |
| Collaboration/Sharing | ✅ Unique URLs | ⚠️ Some | ❌ File-based only |
From Idea to Simulated Circuit in Under 60 Seconds.
Open Circuit IntelliSim
Visit circuit-intelli-sim.longshortlabs.com in any browser. No login. No install. You are in and ready to design.
Describe or Draw Your Circuit
Type what you want in plain English — or drag-and-drop from 500+ components and wire manually in the schematic editor.
Let AI Simulate & Optimise
Click simulate. AI analyses your circuit, runs the simulation, flags issues, and optionally iterates autonomously in agentic mode.
Export, Share, or Build
Download as PDF/SVG, share via unique URL, or use the bill of materials to order components and bring your design to life.
What Engineers & Students Are Saying.
"IntelliSim's agentic simulation saved me 3 days on a switching power supply. I set my efficiency target and the AI delivered an optimised topology. This is the future of circuit design."
Priya R.
Embedded Systems Engineer, Bangalore
"My students run real simulations on their phones during class. The AI co-pilot explains concepts better than most textbooks. It has completely transformed how I teach electronics."
Prof. Arjun M.
Electronics Dept., Chennai
"I had no idea why my audio amplifier was clipping. IntelliSim's AI diagnosed the problem in seconds — incorrect biasing on the second stage. Absolutely game-changing."
Sam K.
Electronics Hobbyist, London
Everything You Need to Know About Circuit IntelliSim.
Circuit IntelliSim is a free, AI-powered, browser-based circuit simulator and schematic editor built by Longshort Labs. It allows engineers, students, and hobbyists to design and simulate analog and digital circuits directly in their browser — with an intelligent AI co-pilot that assists at every step. No installation or sign-up is required.
Yes, Circuit IntelliSim is completely free to use. There is no subscription, no pricing tier, and no sign-up required. Simply visit circuit-intelli-sim.longshortlabs.com in your browser and start designing circuits instantly.
No installation is required. Circuit IntelliSim runs entirely in your web browser on Chrome, Firefox, Safari, and Edge. It works on Windows, Mac, Linux, and tablets.
While traditional circuit simulators like CircuitLab offer schematic editing and SPICE simulation, Circuit IntelliSim goes further with a built-in AI co-pilot that generates circuits from natural language, automatically debugs faults, suggests component optimisations, and runs agentic simulation loops that iteratively improve your design without manual intervention.
Circuit IntelliSim supports analog circuits (amplifiers, filters, oscillators, power supplies), digital circuits (logic gates, counters, flip-flops), and mixed-mode simulations. It includes time-domain, frequency-domain, and DC operating point analyses.
Yes. Circuit IntelliSim is ideal for educators. Students can access it on any device with a browser, with no institutional software licensing required. The AI co-pilot also helps beginners understand circuit concepts interactively.
Agentic circuit simulation means an AI agent autonomously runs multiple simulation iterations, adjusts component values, tests different topologies, and delivers an optimised circuit design — without requiring you to manually intervene in each simulation step. It is one of Circuit IntelliSim's most unique and powerful capabilities.
Yes. Circuit IntelliSim supports export to PDF (vector schematic), SVG, PNG, and EPS. You can also share circuits via unique, shareable URLs.
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