Build digital logic, relay, electricity and analog circuits on one bench. Drag a component, wire it up, and watch every signal flow in real time — from your first AND gate to an 8-bit CPU running assembly you wrote.
Each lab shares the same bench, the same save format, and the same real-time engine — switch domains without switching tools.
THE CORE LAB Simulate logic gates, flip-flops, counters, registers, RAM and a full ALU — 60+ components with live truth tables and probeable signals. Follow the templates all the way to an 8-bit CPU that runs assembly you write yourself.
Electromechanical logic on a real DC solver — coils pull, contacts click, ladder logic latches. 25 guided Blueprints, from one relay to a binary counter.
Open the Relay Lab → NEW
Batteries, bulbs, meters and rheostats. Ohm’s and Kirchhoff’s laws you can see, measure and break — the physics course before the logic course.
Open the Electricity Lab → IN DEVELOPMENT
Op-amps, filters and transistors on an ngspice-accurate SPICE engine compiled to WebAssembly. Paid plans get it when it ships.
Coming to paid plansEvery circuit in the docs, blog and lesson catalog is a live simulation — pause a lesson, flip a switch, and watch the truth table respond. Follow the 18-part Code journey from one clicking relay to a working computer.
Drop any circuit into your LMS, slides or blog as a real interactive simulator — not a screenshot. Classroom adds a teacher dashboard, seat invitations and join codes.
Test a latch, debounce a switch, or size a resistor network in the browser before touching a breadboard. Cloud save keeps your bench, and an AI assistant helps wire and debug circuits with you.
Press play and a finished circuit comes alive: the lesson highlights a component, narrates the idea, then pans to the next. Pause anywhere — every signal stays probeable, because it is still a simulator underneath.
Start free, subscribe monthly or annually, choose the Founder one-time offer while available, or manage Classroom seats.
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Start free≈ $4.83/mo · save 20%
Get Proone payment · no recurring fee
Claim Founder dealbilled annually · from 20 seats
Get seatsAlready own a previous one-time tier? Your existing entitlement is grandfathered, with no new subscription required. Eligible academic accounts receive an automatic discount at checkout. Secure payment by Stripe.
Yes — the logic and electricity sandbox is available at no charge, with up to 30 components, 21 narrated lessons and community templates. No account or install is needed to start.
Logic gates, flip-flops, adders, registers, RAM and full CPUs; relay and ladder logic; DC circuits with batteries, meters and bulbs — and analog op-amps and filters when the Analog Lab ships.
No. DigiSim runs entirely in the browser on any laptop, Chromebook or tablet — the simulation engine is WebAssembly-fast and works offline once loaded.
That’s what it is built for. Embed live circuits in your LMS or slides, assign SimCast lessons, and manage a class with annual per-seat pricing, a teacher dashboard, invitations and join codes.
Pro and Founder plans include every new simulator automatically, at no extra charge. You are never billed for a domain that has not shipped.
Free circuits save locally in your browser; Pro adds cloud save so your bench follows you across devices — plus export for sharing and version history.
No install, no signup to try. Open the bench and start wiring.
