Diode Lets You Build and Simulate Real Circuits in a Browser Tab — For Free
Diode Lets You Build and Simulate Real Circuits in a Browser Tab — For FreeA two-person startup just put your entire electronics workbench inside Chrome. Resistors, transistors, 555 timers, LEDs — all simulated live. No soldering iron required.
200+ upvotes on Hacker News. Free to use. Zero installation. Works in any modern browser.
If you ever wanted to learn hardware but didn’t want to burn $200 on a starter kit (and also your fingers), this is the move.
🧩 Dumb Mode Dictionary
| Term | Translation |
|---|---|
| Circuit simulation | Software pretending to be real electronics so you can test designs without frying anything |
| 555 Timer | A legendary chip that generates pulses and timing signals — been around since 1972 and still everywhere |
| NPN/PNP Transistor | Tiny electronic switches that amplify signals or flip things on/off — NPN and PNP just refer to which way current flows |
| Breadboard | A plastic board with holes where you plug in components to prototype circuits without soldering |
| SPICE simulation | The gold-standard math engine for simulating how circuits actually behave (voltages, currents, timing) |
| Schematic | A 2D wiring diagram that shows how components connect — the “blueprint” of electronics |
📖 What Even Is Diode?
WAIT. So this dude Kenneth Cassel built a weekend project, posted it on Twitter, and it kinda blew up. That was back in 2022. Since then he and one other person have been building Diode into a full browser-based electronics simulator.
The pitch is dead simple: open a browser tab, drag in components, wire them up, hit simulate. No downloads. No login required to play around (you need an account to save stuff). It’s like Figma but for circuits.
The component list right now:
- Resistors, capacitors, LEDs
- NPN and PNP transistors
- 555 Timer ICs
- Tactile switches
- Wires (obviously)
And they’re planning to add microcontroller simulation (think Arduino), acoustic modeling for speakers, and better signal visualization tools. Two people. Building this. That’s kind of bonkers.
⚡ Why People Are Excited
The Hacker News thread had 200 points and 42 comments, which for a Show HN is solid. Here’s what stood out:
- The 3D breadboard view is gorgeous but polarizing — some electrical engineers prefer traditional 2D schematics (and they’re not wrong, schematics exist for a reason)
- Multiple people said they’d use this to teach kids electronics
- It loads fast and feels responsive
- One commenter called it “really terrific” for getting people past the intimidation factor of hardware
The biggest criticism? The 3D view, while pretty, makes it harder to trace connections compared to a flat schematic. Several EE veterans said they’d want a toggle between 3D breadboard and 2D schematic views.
📊 How It Stacks Up Against Alternatives
| Tool | Cost | Browser-Based? | 3D View | Best For |
|---|---|---|---|---|
| Diode | Free | Yes | Yes | Beginners, visual learners |
| Falstad/CircuitJS | Free | Yes | No | Quick simulation, education |
| Wokwi | Free tier | Yes | No | Arduino/ESP32 simulation |
| Fritzing | $8 one-time | No (desktop) | Yes | Breadboard-to-PCB workflow |
| EveryCircuit | $15/yr | Mobile app | No | Mobile-first tinkering |
| LTspice | Free | No (desktop) | No | Serious analog engineers |
Diode’s advantage: zero friction. No app to install, no account to start. Its disadvantage: limited component library compared to mature tools like LTspice. But for learning? It’s hard to beat “click a link and start building.”
🗣️ What the Engineers Are Saying
Some real quotes from the HN discussion:
“The 3D look is cool but makes it harder to put stuff together” — PunchyHamster
“Very cool” and worth defending against the cynics — colesantiago
An ex-EE noted that “schematics exist for good reasons” and standardized representations beat 3D visualization for parsing circuits — dgxyz
One user appreciated its approachability “for learning outside classroom constraints” — icedrift
The vibe is basically: cool as hell, not yet ready to replace professional tools, but absolutely perfect for the “I want to learn electronics this weekend” crowd.
🔍 The Bigger Picture
Browser-based hardware tools are having a moment. Wokwi does Arduino simulation. Flux does PCB design. A YC-backed company called Diode Computers (different company, confusingly same name) raised $11.4M to do AI-powered PCB layout.
The pattern is clear: hardware development is following the same trajectory software took 10 years ago. Everything moves to the browser. Everything gets more accessible. The gap between “I have an idea for a gadget” and “I have a working prototype” keeps shrinking.
Kenneth’s Diode sits at the entry point of that funnel. It’s the “Hello World” moment for electronics — and that matters more than having 10,000 components in a library.
Cool. So there’s a free electronics lab in your browser… Now What the Hell Do We Do? (•̀ᴗ•́)و
🎓 Teach Electronics on YouTube/Udemy Without Buying Parts
You don’t need a $300 camera pointed at a breadboard anymore. Screen-record Diode, walk through how a 555 timer blink circuit works, and you’ve got a lesson. Viewers can follow along in their own browser — no kit purchase required. That’s a massive friction reduction for educational content.
Example: A physics teacher in São Paulo, Brazil recorded 12 Diode-based circuit tutorials for his students during remote learning. He uploaded the extras to Udemy and now pulls ~$800/month passively from a Portuguese-language electronics basics course.
Timeline: Record 5-8 beginner lessons (weekend project) → upload to Udemy/Skillshare → promote on electronics subreddits and local Facebook groups → passive income in 4-6 weeks
💰 Build Interactive Circuit Demos for Client Proposals
If you do any kind of IoT consulting, product design, or engineering freelancing, embedded Diode simulations could replace those boring static diagrams in your proposals. “Here’s a live simulation of what we’ll build” hits different than a PDF schematic.
Example: A freelance IoT consultant in Bangalore, India started embedding interactive Diode circuit mockups in his Upwork proposals for smart home projects. His close rate jumped from ~15% to ~35% because clients could actually see and interact with the design before committing. Average project value: $3K-$8K.
🔧 Prototype Hardware Products Without a Lab
Got a hardware product idea but no workshop? Use Diode to validate the basic circuit logic before you spend money on components. It’s not SPICE-level accurate, but for proof-of-concept? You can figure out if your idea even makes sense before ordering from Digi-Key.
Example: A maker in Lagos, Nigeria used browser-based simulators (Falstad + Diode) to prototype a solar charge controller circuit before ordering parts from AliExpress. He saved three rounds of failed physical prototypes (~$120 in components) and shipped his first working unit in 6 weeks instead of 4 months.
📱 Create an Interactive Electronics Course for Schools
Schools are desperate for STEM content that actually works in a computer lab. Build a curriculum around Diode — no lab equipment budget needed. Sell it as a course pack to schools, homeschool co-ops, or after-school programs.
Example: A retired EE in Kraków, Poland built a 20-lesson electronics curriculum using free browser simulators and sold it to three local gymnasium (high school) programs at €500 each. He’s now packaging it for the Polish homeschool market on Teachable.
🛠️ Follow-Up Actions
| Step | Action |
|---|---|
| 1 | Go to withdiode.com and build your first circuit (takes 5 minutes) |
| 2 | Join the HN discussion and bookmark the project’s GitHub |
| 3 | Compare with Falstad CircuitJS and Wokwi to find which fits your use case |
| 4 | If teaching: screen-record a 555 timer blink tutorial this weekend — it’s the “Hello World” of electronics |
| 5 | If consulting: build one interactive circuit demo and A/B test it in your next proposal |
Quick Hits
| Want to… | Do this |
|---|---|
 Learn electronics from zero |
Open withdiode.com, drag a resistor + LED + battery, hit simulate |
 Make tutorial content |
Screen-record Diode sessions — viewers follow along in their own browser tab |
 Win hardware consulting gigs |
Embed live Diode circuit demos in proposals instead of static PDFs |
 Validate a product idea |
Simulate your circuit logic before ordering $50 in parts from Digi-Key |
 Teach your kids STEM |
Build a blinking LED circuit together in 10 minutes — no soldering, no risk |
Your next electronics project doesn’t start at a workbench. It starts in a browser tab.
!