ScienceExplain Like I'm 5Intermediate
How Electric Circuits Work, a free science course on Tomo

How Electric Circuits Work

Like Duolingo, but for How Electric Circuits Work. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.

For the part of you with thirty open tabs that never became anything.

25 levels across 4 sections, about 50 minutes end to end, roughly 10 days at five minutes a day. It moves through Diagnosing and Predicting DC Loops, Energy Storage and Active Switching, Alternating Signals and Reactive Networks, and The Physical Reality Beneath Schematics. It assumes you already know the basics.

25 bite-size levelsAbout 5 minutes each

Free forever · No credit card · iPhone & Android

Sparky the Sparrow, the guide who teaches the How Electric Circuits Work course
How Electric Circuits Work
with Sparky the Sparrow
25
Levels
4
Sections
5
Min/day
What you'll learn

Key ideas in How Electric Circuits Work

  • Junctions cannot store charge, so total inflow always equals total outflow.
  • Subtracting known outflow branches from the incoming supply yields the remaining branch current.
  • Charge never bottlenecks or vanishes at a circuit node.
  • A closed loop returns to the same electrical potential, making the round-trip net voltage zero.
  • Voltage rises provided by power sources must equal the sum of voltage drops across loads.
  • Kirchhoff's voltage law holds true for any complete loop regardless of branch complexity.
  • Components in a single unbranched path experience the exact same continuous current.
  • Swapping series positions leaves total path resistance and component voltage drops unchanged.
  • Current does not get used up sequentially before reaching downstream components.
  • A voltmeter needs high internal resistance to probe across points without diverting flow.
  • An ammeter must be inserted into an open wire so the full loop current passes through it.
  • Measuring current across a powered component creates an accidental short circuit.
  • Current diverts almost entirely through the near-zero-resistance bypass wire.
  • Bypassed components experience near-zero voltage drop and shut down immediately.
  • Overall circuit resistance collapses, drawing dangerously high current from the power supply.
  • A divider relies on equal current flowing down both series resistors.
Why not just Google it

You've tried the other tabs

Wikipedia

Thirty open tabs. Four facts you actually kept.

YouTube

You watched. You nodded. By Sunday it was gone.

ChatGPT

One answer, then back to scrolling.

Online courses

Eight weeks. You meant to finish. You didn't.

Tomo gives How Electric Circuits Work the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.

Try a question

Here's what playing it feels like

A real question from this course. Take your best guess.

Tracing Loops and Junctions

If 5 amps enter a three-way junction, and two outgoing branches take 2 amps and 1 amp, how much is in the third branch?

Get it right to open this lesson and 24 more in the app.

Course map

Where How Electric Circuits Work takes you

Move beyond basic wiring diagrams to understand how charge, voltage, and energy behave in real-world loops. Learn to diagnose DC loads, master reactive components, control switching, and tame noisy signals.

  1. 1

    Diagnosing and Predicting DC Loops

    • Tracing Voltage and Current with Kirchhoff's Rules
    • Managing Voltage Dividers and Load Effects
  2. 2

    Energy Storage and Active Switching

    • Capacitors in Transient and Filtering Circuits
    • Inductors and Magnetic Transient Spikes
    • Controlling Current with Diodes and Transistors
  3. 3

    Alternating Signals and Reactive Networks

    • Alternating Current and Complex Impedance
    • Passive Filtering and Resonance
  4. 4

    The Physical Reality Beneath Schematics

    • Grounding, Parasitics, and Signal Return

4 sections · 8 units · 25 levels. Built to play, not to enroll.

How it's taught

You pick the voice

This course
Explain Like I'm 5

How Electric Circuits Work is taught in the Explain Like I'm 5 style: no big words. promise.. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.

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Start How Electric Circuits Work today.

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