Definition
An electrical circuit that contains a combination of series and parallel branches, so that current flows through some components in series and through others in parallel within the same circuit.
Plain English
A circuit that mixes both wiring patterns at once. Some parts are wired one after the other (series), and other parts are wired side by side (parallel), all in the same circuit.
Context Anchor
Seen in aircraft electrical-system study, wiring diagrams, and troubleshooting discussions.
Derivation
Complex comes from the Latin complexus, meaning 'woven together.' That fits here: the circuit is 'woven together' from both series and parallel arrangements rather than being one or the other.
Why Pilots Care
Correct understanding prevents misdiagnosis of electrical issues that could affect essential aircraft systems.
Intuition Check
Complex does not just mean “hard to understand” here. It means the circuit is a mixed layout: part series and part parallel.
Example Sentence 1
The aircraft's lighting system is wired as a complex circuit, with the bulbs in parallel and a single switch and fuse in series with the group.
Example Sentence 2
During preflight, the pilot noticed the ammeter behaving oddly and traced the problem to a fault in one branch of the complex circuit feeding the avionics.