Circuit Types
Middle School
Definition
The main ways components are connected in a circuit. In a series circuit there is a single path for the current, while in a parallel circuit there are multiple paths, which affects how current and voltage are shared.
Worked examples
Three bulbs wired one after another on a single loop — if one burns out, all go dark.
This is a series circuit; current has only one path, so breaking it anywhere stops the flow.
Three bulbs each on their own branch from the battery — if one burns out, the others stay lit.
This is a parallel circuit; current splits across multiple paths, so each branch works independently.
Common mistakes
- In a series circuit, voltage is the same across every component. → In a series circuit, current is the same; voltage divides across components. Series shares current equally but splits voltage; parallel does the opposite.
- Adding more bulbs in parallel makes them all dimmer. → In parallel, each bulb gets full battery voltage and stays equally bright. Parallel branches are independent; adding one does not reduce voltage to the others.
- A circuit with one battery and two bulbs must be series. → It depends on the wiring; the bulbs can be in series (one path) or parallel (branching paths). The number of components does not determine circuit type — the connection pattern does.
Where you'll use it next
You'll apply series and parallel analysis when designing circuits, calculating total resistance with resistor rules, and understanding household wiring and safety in later physics and engineering topics.
See also
Reviewed by Pat Cheng, M.Ed. — StudyPug Curriculum Lead · Last updated June 6, 2026