Lesson 3: Electrical Circuits
Electricity powers almost everything in the modern world. Understanding how circuits work gives you the knowledge to understand electronics, build projects, and eventually program hardware.
Key Concepts
Current, Voltage, and Resistance
Current is the flow of electrons (measured in amps). Voltage is the push that drives electrons (measured in volts). Resistance opposes the flow (measured in ohms). Ohm's Law: Voltage = Current × Resistance.
Series and Parallel Circuits
In a series circuit, components are in a single chain — one break stops everything (old Christmas lights). In a parallel circuit, components have separate paths — one break does not stop the others (modern lighting).
Short Circuits
A short circuit is a path with almost no resistance. All the current rushes through it instead of the intended path. This can cause overheating and fires. Fuses and circuit breakers protect against short circuits.
🆕 Circuit Builder
Build series and parallel circuits. See how current flows!
✅ Check Your Understanding
1. What is voltage?
2. In a series circuit, what happens when one component breaks?
3. In a parallel circuit, what happens when one branch breaks?