Definition
A small indicator lamp on a test instrument or panel that illuminates when an unbroken electrical path exists between two points in a circuit being tested.
Plain English
A little light that turns on if electricity can flow all the way through a wire or circuit. If the light comes on, the path is complete. If it stays off, the path is broken somewhere.
Context Anchor
Seen in aircraft electrical system troubleshooting and maintenance checks, especially when checking switches, wires, fuses, and connections.
Derivation
‘Continuity’ comes from the Latin continuus, meaning ‘uninterrupted’ or ‘joined together.’ In electrical work, continuity means the path is unbroken — current can travel from one end to the other without a gap.
Why Pilots Care
A pilot doesn’t use a continuity light in flight, but understanding the term helps when reading maintenance logs, talking to mechanics, or troubleshooting electrical squawks. A circuit that fails a continuity check is a circuit that can’t do its job.
Grounding Statement
A continuity light is a simple yes-or-no check for an unbroken electrical path.
Intuition Check
Do not assume a glowing continuity light means the component is fully good. It only shows that an electrical path exists between the points being tested.
Example Sentence 1
The mechanic used a continuity light to check the wiring between the landing gear switch and the warning horn.
Example Sentence 2
No light appeared on the continuity light, revealing an open wire in the navigation light harness.