What a learner can do afterwards
- States the rules for current and voltage in series circuits (current same everywhere; voltages add up)
- States the rules for current and voltage in parallel circuits (voltages same across each branch; currents add up)
- Explains why household wiring uses parallel circuits and identifies the advantage of each type
The lesson
You already know that current flows through a circuit at some voltage and meets some resistance along the way. Now look at how the parts are arranged. There are two main patterns: series and parallel.
In a series circuit, there is only one path for current to flow. That means the current is exactly the same at every point in the loop. The voltage, though, splits: each part uses some of it, and those voltage drops add up to the battery's total voltage.
In a parallel circuit, the parts sit on separate branches. Each branch connects straight across the battery, so every branch gets the full voltage. The current is what splits this time: it divides between branches, and those branch currents add up to the total current the battery supplies.
Every lamp in your house is wired in parallel, so each one gets full voltage and works on its own path. Turn off one light and the others stay on. Old-style Christmas lights are wired in series instead, so one broken bulb breaks the only path, and the whole string goes dark.
Series shares one path, so current stays the same while voltage splits; parallel gives every branch full voltage while the currents add up.
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Where it sits
Learn first
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Nothing builds on it yet.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.