LIVE · 149 component pages and counting

Every component.
Every formula. One hub.

A free, offline-first electronics handbook and study hub — plain-English datasheets for 149+ components, 46 circuit calculators, 7,900+ previous-year question papers, DCET mock tests with analytics, unit converters and a quiz mode. No sign-in needed, no ads.

Free · Offline-capable · No sign-in required

led_driver.sch
+9V330 Ωred LEDI = (9 − 2.0) / 330≈ 21.2 mA ✓
149+
Components documented
46
Calculators & decoders
7,900+
Question papers
100%
Free & offline
01 · What is ElectroHub

The datasheet, translated into human

Real datasheets are 40 pages of graphs written for people who already know the answer. ElectroHub is the opposite: every component gets one clear page — what it does, how to read its markings, which one to buy, the pinout, how it fails and how to test it. Calculators, converters and a quiz round it out into a complete bench-side companion that works with the Wi-Fi down.

Students

Prepping for a lab viva or electronics exam? Every page doubles as revision notes, and quiz mode drills the questions examiners actually ask.

Makers & hobbyists

Mid-build and can't remember which way the electrolytic cap goes? Pull up the pinout, check the polarity, decode the bands — done.

Engineers & technicians

A fast second brain at the bench: failure modes, multimeter test procedures and code decoders without digging through PDF datasheets.

02 · How it works

From “what’s this part?” to “circuit works” in four steps

No tutorials to sit through. Open it, look things up, get back to building.

  1. Find your part

    Browse 14 categories or type a part name like "555 timer" into search and jump straight to it.

    Browse components
  2. Read the plain-English page

    What it does, key specs, markings, which one to buy, the pinout, how it fails and how to test it with a multimeter.

    Try search
  3. Run the numbers

    46 calculators that show their working step by step, and converters that flip units both ways. No spreadsheet needed.

    Open calculators
  4. Make it stick

    Quiz mode turns the library into practice questions per category — ideal for viva prep and interviews.

    Start a quiz
03 · Toolbox

Everything a bench-side companion should have

Component library

100+ components across 9 categories — specs, markings, how-to-choose, pinouts, failure modes and test procedures in plain English.

Handy calculators

A guided circuit solver and 45 syllabus-aligned tools with step-by-step working — from Ohm's law and star-delta to three-phase power, op-amps and the 555 timer.

Fast search

Find any part by name, type or spec in milliseconds. Filter by availability so you only see what's ready to read.

Unit converters

Flip between µF and nF, mA and A, dBm and mW without thinking twice — bidirectional converters for the units you actually use.

Quiz mode

Practice viva and exam questions per category. Great for lab exams, interviews and keeping the fundamentals sharp.

Works offline

Installable as a PWA. Once loaded, the entire reference runs without a network connection — perfect for the lab bench.

06 · Calculators

Calculators that actually solve the problem

Stop tabbing out to a spreadsheet. A guided circuit solver and 45 purpose-built calculators cover the math you do every day — every answer shows its step-by-step working, and every code decoder works both ways.

  • Ohm's law & power — solve for V, I, R or P from any two values
  • LED series resistor — pick the right R for your LED
  • Star ↔ delta and Wheatstone bridge — network transforms made painless
  • RLC impedance, reactance and resonance — full AC analysis
  • Three-phase power and power triangle — kW, kVA, kVAR and cos φ
  • Transformer — turns ratio, voltage and current both ways
  • 555 timer and op-amp gain — design the circuit, not just check it
  • Color, capacitor and SMD codes — decode or encode, both directions
Ohm's Law
V = I × R
Power
P = V × I
LED Resistor
R = (Vs−Vf) / If
Color Code
4 & 5 band

Power up your next build

The whole reference is one tap away — and once it loads, it's yours offline too.

Open ElectroHub — it's free

Tip: use your browser's Add to Home Screen to install ElectroHub like an app — it keeps working with no connection at all.