Free electronics tools & study resources

Electronics,
made clear.

A working hub for electronics — precision calculators and interactive tools that show their work, plus complete Associate CET exam prep with lessons, practice questions, and reference. Whether you're building, troubleshooting, or studying, it's all here. Free, no account, works offline.

30+
Tools & calculators
26
Instant calculators
445
Practice questions
20
Exam topic areas

Study & practice

START HERE

The core of your prep: learn the concepts, test yourself, and track where you stand.

🎓
Study HubStart here
Your home base for exam prep, in one place: 33 guided lessons covering every competency area, a 479-question practice quiz, and a full-length timed mock exam. Miss a question and it points you straight to the lesson that covers it.
Enter the Study Hub →
📊Track
Study Dashboard
See your quiz and mock-exam history, score trends, and which competencies need the most work.
View progress →
🧪Build
Circuits Lab
An interactive simulator — build series and parallel circuits, change values, and watch voltage, current, and power update live. AC reactance too.
Open the simulator →
📐Learn
Algebra Trainer
Rearrange real electronics formulas with a live symbolic engine that checks every step you take.
Train algebra →
🃏Drill
Flashcards
190 cards across formulas, symbols, and definitions — flip, shuffle, and filter by deck.
Study cards →
📋Review
Formula Cheat Sheet
Every core Associate CET formula on one page for fast last-minute review before exam day.
Open cheat sheet →
🔌Visualize
Antenna Build Lab
See what real antennas look like — dipole, G5RV, vertical, Yagi — drawn to your frequency.
Build antennas →

Associate CET competency map

20 EXAM TOPIC AREAS

The full Associate CET exam blueprint — all 20 competency areas, every one covered by tools and reference here. Once you start taking quizzes, each tile also shows your mastery, so you can see at a glance where you're solid and where to aim next.

These tiles color from your quiz and mock-exam scores — take a quiz in the Circuits Lab to light them up. A tile only turns green once you've answered at least 8 questions in that area and scored 75%+, so a full board of green genuinely means exam-ready — not a lucky few questions. Flashcard progress is tracked separately on your Study Dashboard.

Strong — 75%+ (8+ answered) Building — 50–74% Needs work — under 50% In progress — under 8 answered Not yet tested

Tools & reference

CALCULATE & LOOK UP

Precision calculators that show their work, plus a full reference library.

⚡
Calculator Suite
26 instant calculators in one place — Ohm's law, power, reactance, impedance, resonance, time constants, filters, and the math tools (algebra, trig, stats, fractions).
Open the suite →
 📚
Reference Library
Circuit symbols, component values, IC pinouts, semiconductor basics, the schematic-reading guide, and a searchable glossary of Associate CET terms.
Browse reference →