Free online circuit simulator with a real Arduino inside.
Drag parts onto a grid, route wires, run an Arduino sketch, probe with a multimeter or oscilloscope. Real DC + transient simulation under the hood — LEDs light at the right current, capacitors charge on a real RC curve, parts can burn out if you wire them wrong. No install. No Spice. Just a browser tab.
No install · No credit card · Works in any modern browser
What's inside ExoSynk Lab
A real workbench — same parts and instruments you'd use on a real breadboard, simulated honestly.
Schematic editor
Drag from a parts palette, snap to grid, route wires with junction dots and hops. Full keyboard shortcuts. Auto-simulates as you change the circuit.
DC + transient simulation
Modified Nodal Analysis solves Ohm/KCL/KVL exactly. The transient solver follows capacitor charge curves, RC time constants, and time-varying inputs.
Virtual Arduino Uno
Full ATmega328 emulator. Write the same Arduino C++ you'd write on hardware — digitalWrite, analogRead, PWM, Serial. Pins drive simulated LEDs and read simulated voltages in real time.
Multimeter + oscilloscope
Probe any node for voltage or current. Two-channel scope with adjustable timebase. Voltage-gradient overlay paints the whole circuit so you can see where charge is flowing.
Honest parts library
Resistors, capacitors, LEDs, diodes, transistors, switches, batteries, 555 timer, 74LS logic gates, op-amps, buzzers, 7-segment displays. Components have real datasheet behavior — LEDs have forward voltages, transistors have gain curves.
Public labs you can fork
Make a lab public and anyone can open it, run it, and fork it. Every project gets a clean URL like exosynk.com/your-handle/your-project. Comments and upvotes attached to every lab.
Why use an online circuit simulator?
Most electronics projects fail on the breadboard for predictable reasons — wrong resistor on an LED, a transistor wired backwards, a capacitor charging through the wrong path. ExoSynk Lab lets you catch those mistakes in the browser before you ever pick up a soldering iron. It runs the same physics a real circuit does, then shows you the answer: current through every wire, voltage on every node, and which parts are about to burn.
Built for Arduino projects
The virtual Arduino Uno isn't a stub. It executes real AVR machine code compiled from your sketch. That means anything you can run on a physical Uno — blink, button debouncing, PWM dimming, serial protocols, sensor reading — runs the same way here. Drop an LED on pin 13, write digitalWrite(13, HIGH), and the LED lights at exactly the current its datasheet says it should.
Frequently asked questions
Is ExoSynk Lab free?+
Yes. The 2D circuit lab, virtual Arduino, multimeter, and oscilloscope are all free. You only need an account to save your work to the cloud and publish public labs.
Do I need to install anything?+
No. ExoSynk runs entirely in the browser. No Spice, no Arduino IDE, no toolchain to configure. Works on any modern browser — Chrome, Edge, Firefox, Safari.
What microcontroller does it simulate?+
ExoSynk includes a virtual Arduino Uno (ATmega328) with digital and analog pins, PWM, and a serial monitor. You write the same Arduino C++ you would on hardware.
Is the simulation real or just animation?+
Real. ExoSynk uses Modified Nodal Analysis for DC simulation and a transient solver for time-varying circuits. LEDs light at their correct current, capacitors follow RC curves, and parts can burn out.
Can I share my circuits?+
Yes. Every public lab gets a clean URL (exosynk.com/your-handle/your-project). Anyone can view it, run the simulation, and fork it.
How does ExoSynk compare to Tinkercad or Wokwi?+
ExoSynk is open by design — fork any public lab, comment, follow other builders, and publish tutorials linked to runnable circuits. It also integrates a 3D modeler for enclosures and a marketplace for printable parts.
Build a real circuit in 30 seconds.
No installs, no signups required to try it. Free forever for personal projects.