Short answer
Components are in series when current must pass through one and then the next along the same path. They are in parallel when each connects across the same pair of nodes, giving current alternative paths. Most real circuits mix both arrangements. 1 2
Series components share current; parallel branches share voltage between common nodes.
On this page
At a glance
Scroll to compare all columns →
| Question | Series connection | Parallel connection |
|---|---|---|
| Paths through components | One successive path | Separate branches |
| Shared quantity in ideal analysis | Same current | Same voltage |
| If one branch opens | Whole path may break | Other branches may remain |
The table summarizes the cited definitions and the article’s stated scope. 1 2
What each thing is
Series connection. A connection in which the same current path passes successively through the components. 1
Parallel connection. A connection in which components connect across the same two nodes, forming alternative branches. 1
Key differences
OpenStax’s resistor examples show the topology difference. In series, current cannot choose between components. In parallel, junctions split and recombine current while branch endpoints are common. 1 2
How to tell them apart
Trace nodes on a diagram, not the physical arrangement on a board. Two parts are parallel only if both ends connect to the same respective nodes; they are series if their shared node has no other branch. 1 2
Where they overlap
Both are ways to connect components in one electrical network. A circuit may contain a parallel pair placed in series with another part, so the label belongs to a specified set of components. 1 2
Edge cases
A wire routing that looks side-by-side need not be electrically parallel. If extra branches join the supposed series midpoint, the same-current rule may fail. Complex networks cannot always be reduced to simple series and parallel groups. 1 2
Why the distinction exists
Topology determines current division, voltage distribution and equivalent resistance, which guides circuit design and troubleshooting. 1 2
Common misconceptions
“Next to each other” is not the electrical definition of parallel. Series and parallel describe node connections. 1 2
Examples
Two lamps in one unbranched loop are in series. Two lamps each connected between the same supply nodes are in parallel. 1 2
Sources
Sources checked October 3, 2026.
- OpenStax — Resistors in Series and Parallel. Series; Parallel.
- OpenStax — Current. Current and circuit.