Linked from
The 16 pages that link to Electric circuit, each with the reason it gives.
Direct currentNarrower topic: Direct current is analyzed as flow through a connected circuit.
Short circuitNarrower topic: A short circuit is a fault within an otherwise intended circuit.
Electric batteryNarrower topic: A battery supplies energy only when connected in a closed circuit.
Ampere-hourNarrower topic: The unit quantifies charge passing through a circuit over time.
Knife switchNarrower topic: The knife switch changes whether its circuit has a conducting path.